<?xml version="1.0" encoding="us-ascii"?>
<!-- DFIN ActiveDisclosure(SM) XBRL Linkbase Document - http://www.dfinsolutions.com/ -->
<!-- Creation Date      : 2020-12-07T19:54:22.8932944+00:00 -->
<!-- Version            : 5.0.1.569 -->
<!-- Package ID         : 9c5d19192efb496baee9919e595a5445 -->
<!-- Copyright (c) 2020 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" />
  <link:roleRef xlink:type="simple" xlink:href="sgu-20200930.xsd#TemplateLink" roleURI="http://www.stargrouplp.com/20200930/role/TemplateLink" />
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:href="sgu-20200930.xsd#Role_StatementCONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFOPERATIONS">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted" xlink:type="locator" xlink:label="us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract" xlink:type="locator" xlink:label="us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax" xlink:type="locator" xlink:label="us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLossAllocatedToLimitedPartners" xlink:type="locator" xlink:label="us-gaap_NetIncomeLossAllocatedToLimitedPartners" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLossAllocatedToGeneralPartners" xlink:type="locator" xlink:label="us-gaap_NetIncomeLossAllocatedToGeneralPartners" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss" xlink:type="locator" xlink:label="us-gaap_NetIncomeLoss" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:type="locator" xlink:label="us-gaap_IncomeTaxExpenseBenefit" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:type="locator" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:type="locator" xlink:label="us-gaap_OtherNonoperatingIncomeExpense" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherDepreciationAndAmortization" xlink:type="locator" xlink:label="us-gaap_OtherDepreciationAndAmortization" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRevenueExpenseNet" xlink:type="locator" xlink:label="us-gaap_InterestRevenueExpenseNet" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:type="locator" xlink:label="us-gaap_OperatingIncomeLoss" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherOperatingIncome" xlink:type="locator" xlink:label="us-gaap_OtherOperatingIncome" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:type="locator" xlink:label="us-gaap_GeneralAndAdministrativeExpense" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DepreciationAndAmortization" xlink:type="locator" xlink:label="us-gaap_DepreciationAndAmortization" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingCostsAndExpenses" xlink:type="locator" xlink:label="us-gaap_OperatingCostsAndExpenses" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnrealizedGainLossOnDerivatives" xlink:type="locator" xlink:label="us-gaap_UnrealizedGainLossOnDerivatives" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold" xlink:type="locator" xlink:label="us-gaap_CostOfGoodsAndServicesSold" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingCostsAndExpensesAbstract" xlink:type="locator" xlink:label="us-gaap_OperatingCostsAndExpensesAbstract" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:type="locator" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenuesAbstract" xlink:type="locator" xlink:label="us-gaap_RevenuesAbstract" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CostOfInstallationsAndServicesMember" xlink:type="locator" xlink:label="sgu_CostOfInstallationsAndServicesMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CostOfProductMember" xlink:type="locator" xlink:label="sgu_CostOfProductMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_InstallationAndServicesMember" xlink:type="locator" xlink:label="sgu_InstallationAndServicesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProductMember" xlink:type="locator" xlink:label="us-gaap_ProductMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:type="locator" xlink:label="srt_ProductsAndServicesDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:type="locator" xlink:label="srt_ProductsAndServicesDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis" xlink:type="locator" xlink:label="srt_ProductOrServiceAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:type="locator" xlink:label="us-gaap_StatementTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:type="locator" xlink:label="us-gaap_StatementLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" order="10150.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable" xlink:to="srt_ProductOrServiceAxis" order="10180.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_ProductOrServiceAxis" xlink:to="srt_ProductsAndServicesDomain_2" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_ProductOrServiceAxis" xlink:to="srt_ProductsAndServicesDomain" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain" xlink:to="us-gaap_ProductMember" order="10230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain" xlink:to="sgu_InstallationAndServicesMember" order="10250.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain" xlink:to="sgu_CostOfProductMember" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain" xlink:to="sgu_CostOfInstallationsAndServicesMember" order="10290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_RevenuesAbstract" order="10320.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RevenuesAbstract" xlink:to="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" order="10440.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OperatingCostsAndExpensesAbstract" order="10620.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingCostsAndExpensesAbstract" xlink:to="us-gaap_CostOfGoodsAndServicesSold" order="10740.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingCostsAndExpensesAbstract" xlink:to="us-gaap_UnrealizedGainLossOnDerivatives" order="10860.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingCostsAndExpensesAbstract" xlink:to="us-gaap_OperatingCostsAndExpenses" order="10920.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingCostsAndExpensesAbstract" xlink:to="us-gaap_DepreciationAndAmortization" order="10980.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingCostsAndExpensesAbstract" xlink:to="us-gaap_GeneralAndAdministrativeExpense" order="11040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingCostsAndExpensesAbstract" xlink:to="us-gaap_OtherOperatingIncome" order="11100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OperatingIncomeLoss" order="11160.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_InterestRevenueExpenseNet" order="11220.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OtherDepreciationAndAmortization" order="11280.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OtherNonoperatingIncomeExpense" order="11340.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" order="11400.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_IncomeTaxExpenseBenefit" order="11460.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_NetIncomeLoss" order="11520.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_NetIncomeLossAllocatedToGeneralPartners" order="11580.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_NetIncomeLossAllocatedToLimitedPartners" order="11640.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax" order="11760.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract" order="11820.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract" xlink:to="us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted" order="11940.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFPARTNERSCAPITAL" xlink:href="sgu-20200930.xsd#Role_StatementCONSOLIDATEDSTATEMENTSOFPARTNERSCAPITAL" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFPARTNERSCAPITAL">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountingStandardsUpdateExtensibleList" xlink:type="locator" xlink:label="us-gaap_AccountingStandardsUpdateExtensibleList" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:type="locator" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" xlink:type="locator" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PartnersCapitalAccountDistributions" xlink:type="locator" xlink:label="us-gaap_PartnersCapitalAccountDistributions" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansObligation" xlink:type="locator" xlink:label="sgu_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansObligation" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss" xlink:type="locator" xlink:label="us-gaap_NetIncomeLoss" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_TaxCutsAndJobsActOf2017ReclassificationOfStandardTaxEffectsFromTaxReform" xlink:type="locator" xlink:label="sgu_TaxCutsAndJobsActOf2017ReclassificationOfStandardTaxEffectsFromTaxReform" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PartnersCapitalAccountUnits" xlink:type="locator" xlink:label="us-gaap_PartnersCapitalAccountUnits" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PartnersCapital" xlink:type="locator" xlink:label="us-gaap_PartnersCapital" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember" xlink:type="locator" xlink:label="srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain" xlink:type="locator" xlink:label="srt_CumulativeEffectPeriodOfAdoptionDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain" xlink:type="locator" xlink:label="srt_CumulativeEffectPeriodOfAdoptionDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis" xlink:type="locator" xlink:label="srt_CumulativeEffectPeriodOfAdoptionAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GeneralPartnerMember" xlink:type="locator" xlink:label="us-gaap_GeneralPartnerMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:type="locator" xlink:label="us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:type="locator" xlink:label="us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:type="locator" xlink:label="us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:type="locator" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockMember" xlink:type="locator" xlink:label="us-gaap_CommonStockMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain" xlink:type="locator" xlink:label="us-gaap_EquityComponentDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain" xlink:type="locator" xlink:label="us-gaap_EquityComponentDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:type="locator" xlink:label="us-gaap_StatementEquityComponentsAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:type="locator" xlink:label="us-gaap_StatementTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:type="locator" xlink:label="us-gaap_StatementLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementEquityComponentsAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_CommonStockMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" order="10140.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:to="us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_2" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:to="us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:to="us-gaap_GeneralPartnerMember" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable" xlink:to="srt_CumulativeEffectPeriodOfAdoptionAxis" order="10220.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_CumulativeEffectPeriodOfAdoptionAxis" xlink:to="srt_CumulativeEffectPeriodOfAdoptionDomain_2" order="10230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_CumulativeEffectPeriodOfAdoptionAxis" xlink:to="srt_CumulativeEffectPeriodOfAdoptionDomain" order="10250.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_CumulativeEffectPeriodOfAdoptionDomain" xlink:to="srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_PartnersCapital" order="10320.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_PartnersCapitalAccountUnits" order="10340.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="sgu_TaxCutsAndJobsActOf2017ReclassificationOfStandardTaxEffectsFromTaxReform" order="10460.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_NetIncomeLoss" order="10600.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" order="10740.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="sgu_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansObligation" order="10880.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax" order="11020.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax" order="11160.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax" order="11300.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax" order="11440.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_PartnersCapitalAccountDistributions" order="11580.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" order="11720.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" order="11740.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AccountingStandardsUpdateExtensibleList" order="12140.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureOrganizationAdditionalInformationDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureOrganizationAdditionalInformationDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureOrganizationAdditionalInformationDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtConversionOriginalDebtDueDateOfDebtDayMonthAndYear" xlink:type="locator" xlink:label="us-gaap_DebtConversionOriginalDebtDueDateOfDebtDayMonthAndYear" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_LineOfCreditFacilityMaximumBorrowingCapacityDuringHeatingSeason" xlink:type="locator" xlink:label="sgu_LineOfCreditFacilityMaximumBorrowingCapacityDuringHeatingSeason" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTerm" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentTerm" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentFaceAmount" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_NumberOfCustomersToWhomSellGasolineAndDieselFuel" xlink:type="locator" xlink:label="sgu_NumberOfCustomersToWhomSellGasolineAndDieselFuel" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_NumberOfServiceContractsForNaturalGasAndOtherHeatingSystems" xlink:type="locator" xlink:label="sgu_NumberOfServiceContractsForNaturalGasAndOtherHeatingSystems" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_NumberOfCustomersToWhomOnlyHomeHeatingOilGasolineAndDieselWereSellsOnDeliveryOnlyBasis" xlink:type="locator" xlink:label="sgu_NumberOfCustomersToWhomOnlyHomeHeatingOilGasolineAndDieselWereSellsOnDeliveryOnlyBasis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_NumberOfResidentialAndCommercialHomeHeatingOilAndPropaneCustomersServed" xlink:type="locator" xlink:label="sgu_NumberOfResidentialAndCommercialHomeHeatingOilAndPropaneCustomersServed" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_EquityMethodInvestmentAcquiredOwnershipPercentage" xlink:type="locator" xlink:label="sgu_EquityMethodInvestmentAcquiredOwnershipPercentage" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest" xlink:type="locator" xlink:label="us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest" xlink:type="locator" xlink:label="us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest" xlink:type="locator" xlink:label="us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PartnersCapitalAccountUnits" xlink:type="locator" xlink:label="us-gaap_PartnersCapitalAccountUnits" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NumberOfReportableSegments" xlink:type="locator" xlink:label="us-gaap_NumberOfReportableSegments" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_TermLoanMember" xlink:type="locator" xlink:label="sgu_TermLoanMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:type="locator" xlink:label="us-gaap_CreditFacilityDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:type="locator" xlink:label="us-gaap_CreditFacilityDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:type="locator" xlink:label="us-gaap_CreditFacilityAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_FifthAmendmentMember" xlink:type="locator" xlink:label="sgu_FifthAmendmentMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityLenderDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityLenderDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityAxis" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_SubsidiariesTwoMember" xlink:type="locator" xlink:label="sgu_SubsidiariesTwoMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SubsidiariesMember" xlink:type="locator" xlink:label="srt_SubsidiariesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:type="locator" xlink:label="srt_ConsolidatedEntitiesDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:type="locator" xlink:label="srt_ConsolidatedEntitiesDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:type="locator" xlink:label="srt_ConsolidatedEntitiesAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_StarGroupLPMember" xlink:type="locator" xlink:label="sgu_StarGroupLPMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_OwnershipDomain" xlink:type="locator" xlink:label="srt_OwnershipDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_OwnershipDomain" xlink:type="locator" xlink:label="srt_OwnershipDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_OwnershipAxis" xlink:type="locator" xlink:label="srt_OwnershipAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockMember" xlink:type="locator" xlink:label="us-gaap_CommonStockMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain" xlink:type="locator" xlink:label="us-gaap_EquityComponentDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:type="locator" xlink:label="us-gaap_StatementEquityComponentsAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GeneralPartnerMember" xlink:type="locator" xlink:label="us-gaap_GeneralPartnerMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:type="locator" xlink:label="us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:type="locator" xlink:label="us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:type="locator" xlink:label="us-gaap_LimitedPartnersCapitalAccountLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:to="us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable" xlink:to="us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:to="us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:to="us-gaap_GeneralPartnerMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable" xlink:to="us-gaap_StatementEquityComponentsAxis" order="10100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_CommonStockMember" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable" xlink:to="srt_OwnershipAxis" order="10160.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_OwnershipAxis" xlink:to="srt_OwnershipDomain_2" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_OwnershipAxis" xlink:to="srt_OwnershipDomain" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain" xlink:to="sgu_StarGroupLPMember" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable" xlink:to="srt_ConsolidatedEntitiesAxis" order="10240.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_ConsolidatedEntitiesAxis" xlink:to="srt_ConsolidatedEntitiesDomain_2" order="10250.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_ConsolidatedEntitiesAxis" xlink:to="srt_ConsolidatedEntitiesDomain" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ConsolidatedEntitiesDomain" xlink:to="srt_SubsidiariesMember" order="10290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_OwnershipDomain" xlink:to="sgu_SubsidiariesTwoMember" order="10430.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable" xlink:to="us-gaap_LineOfCreditFacilityAxis" order="10440.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_LineOfCreditFacilityAxis" xlink:to="us-gaap_LineOfCreditFacilityLenderDomain_2" order="10450.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_LineOfCreditFacilityAxis" xlink:to="us-gaap_LineOfCreditFacilityLenderDomain" order="10470.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLenderDomain" xlink:to="sgu_FifthAmendmentMember" order="10490.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable" xlink:to="us-gaap_CreditFacilityAxis" order="10580.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_CreditFacilityAxis" xlink:to="us-gaap_CreditFacilityDomain_2" order="10590.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_CreditFacilityAxis" xlink:to="us-gaap_CreditFacilityDomain" order="10610.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="sgu_TermLoanMember" order="10630.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:to="us-gaap_NumberOfReportableSegments" order="10680.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:to="us-gaap_PartnersCapitalAccountUnits" order="10730.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:to="us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest" order="10750.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:to="us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest" order="10790.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:to="us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest" order="10840.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:to="sgu_EquityMethodInvestmentAcquiredOwnershipPercentage" order="10860.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:to="sgu_NumberOfResidentialAndCommercialHomeHeatingOilAndPropaneCustomersServed" order="10880.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:to="sgu_NumberOfCustomersToWhomOnlyHomeHeatingOilGasolineAndDieselWereSellsOnDeliveryOnlyBasis" order="10900.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:to="sgu_NumberOfServiceContractsForNaturalGasAndOtherHeatingSystems" order="10920.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:to="sgu_NumberOfCustomersToWhomSellGasolineAndDieselFuel" order="10940.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:to="us-gaap_DebtInstrumentFaceAmount" order="10990.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:to="us-gaap_DebtInstrumentTerm" order="11010.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:to="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" order="11030.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:to="sgu_LineOfCreditFacilityMaximumBorrowingCapacityDuringHeatingSeason" order="11050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LimitedPartnersCapitalAccountLineItems" xlink:to="us-gaap_DebtConversionOriginalDebtDueDateOfDebtDayMonthAndYear" order="11070.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeNotionalAmount" xlink:type="locator" xlink:label="us-gaap_DerivativeNotionalAmount" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeGainLossOnDerivativeNet" xlink:type="locator" xlink:label="us-gaap_DerivativeGainLossOnDerivativeNet" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DerivativeMaximumPayoutUnderWeatherHedgeContract" xlink:type="locator" xlink:label="sgu_DerivativeMaximumPayoutUnderWeatherHedgeContract" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_RightToReceivePaymentUnderWeatherHedgeContract" xlink:type="locator" xlink:label="sgu_RightToReceivePaymentUnderWeatherHedgeContract" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_AdditionalPaymentObligatedToPayIfDegreeDaysExceedTenYearAverage" xlink:type="locator" xlink:label="sgu_AdditionalPaymentObligatedToPayIfDegreeDaysExceedTenYearAverage" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExaminationLikelihoodOfUnfavorableSettlement" xlink:type="locator" xlink:label="us-gaap_IncomeTaxExaminationLikelihoodOfUnfavorableSettlement" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdvertisingExpense" xlink:type="locator" xlink:label="us-gaap_AdvertisingExpense" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherExpenses" xlink:type="locator" xlink:label="us-gaap_OtherExpenses" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_RecognitionOfUnmotizedDeferredLiabilities" xlink:type="locator" xlink:label="sgu_RecognitionOfUnmotizedDeferredLiabilities" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromDivestitureOfBusinesses" xlink:type="locator" xlink:label="us-gaap_ProceedsFromDivestitureOfBusinesses" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:type="locator" xlink:label="us-gaap_OtherNonoperatingIncomeExpense" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_LiabilitiesHeldForSaleNotPartOfDisposalGroup" xlink:type="locator" xlink:label="sgu_LiabilitiesHeldForSaleNotPartOfDisposalGroup" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainLossOnDispositionOfAssets1" xlink:type="locator" xlink:label="us-gaap_GainLossOnDispositionOfAssets1" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsHeldForSaleNotPartOfDisposalGroup" xlink:type="locator" xlink:label="us-gaap_AssetsHeldForSaleNotPartOfDisposalGroup" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetUsefulLife" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MinimumPercentageOfLikelihoodOnGoodwillImpairment" xlink:type="locator" xlink:label="sgu_MinimumPercentageOfLikelihoodOnGoodwillImpairment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GoodwillImpairmentLoss" xlink:type="locator" xlink:label="us-gaap_GoodwillImpairmentLoss" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NumberOfReportableSegments" xlink:type="locator" xlink:label="us-gaap_NumberOfReportableSegments" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MutualFundMeasurementInvestmentAtNetAssets" xlink:type="locator" xlink:label="sgu_MutualFundMeasurementInvestmentAtNetAssets" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsNoncurrent" xlink:type="locator" xlink:label="us-gaap_RestrictedCashAndCashEquivalentsNoncurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:type="locator" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" xlink:type="locator" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CashEquivalentsMaturityPeriod" xlink:type="locator" xlink:label="sgu_CashEquivalentsMaturityPeriod" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRateSwapMember" xlink:type="locator" xlink:label="us-gaap_InterestRateSwapMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:type="locator" xlink:label="us-gaap_DerivativeContractTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:type="locator" xlink:label="us-gaap_DerivativeContractTypeDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:type="locator" xlink:label="us-gaap_DerivativeInstrumentRiskAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountingStandardsUpdate201602Member" xlink:type="locator" xlink:label="us-gaap_AccountingStandardsUpdate201602Member" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:type="locator" xlink:label="us-gaap_TypeOfAdoptionMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:type="locator" xlink:label="us-gaap_TypeOfAdoptionMember_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:type="locator" xlink:label="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_OperatingCostsAndExpensesMember" xlink:type="locator" xlink:label="sgu_OperatingCostsAndExpensesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioForecastMember" xlink:type="locator" xlink:label="srt_ScenarioForecastMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="srt_ScenarioUnspecifiedDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="srt_ScenarioUnspecifiedDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementScenarioAxis" xlink:type="locator" xlink:label="srt_StatementScenarioAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_FinancialProductsCorporationMember" xlink:type="locator" xlink:label="sgu_FinancialProductsCorporationMember" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityDomain" xlink:type="locator" xlink:label="dei_EntityDomain" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityDomain" xlink:type="locator" xlink:label="dei_EntityDomain_2" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_LegalEntityAxis" xlink:type="locator" xlink:label="dei_LegalEntityAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OilAndGasPropertiesMember" xlink:type="locator" xlink:label="us-gaap_OilAndGasPropertiesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventMember" xlink:type="locator" xlink:label="us-gaap_SubsequentEventMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:type="locator" xlink:label="us-gaap_SubsequentEventTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:type="locator" xlink:label="us-gaap_SubsequentEventTypeDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:type="locator" xlink:label="us-gaap_SubsequentEventTypeAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_OperatingLeaseObligationsMember" xlink:type="locator" xlink:label="sgu_OperatingLeaseObligationsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:type="locator" xlink:label="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:type="locator" xlink:label="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByLiabilityClassAxis" xlink:type="locator" xlink:label="us-gaap_FairValueByLiabilityClassAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_OperatingLeaseRightUseOfAssetsMember" xlink:type="locator" xlink:label="sgu_OperatingLeaseRightUseOfAssetsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentMember" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IndefinitelivedIntangibleAssetsMember" xlink:type="locator" xlink:label="us-gaap_IndefinitelivedIntangibleAssetsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GoodwillMember" xlink:type="locator" xlink:label="us-gaap_GoodwillMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:type="locator" xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:type="locator" xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByAssetClassAxis" xlink:type="locator" xlink:label="us-gaap_FairValueByAssetClassAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TradeNamesMember" xlink:type="locator" xlink:label="us-gaap_TradeNamesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CustomerListsMember" xlink:type="locator" xlink:label="us-gaap_CustomerListsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:type="locator" xlink:label="us-gaap_FairValueInputsLevel1Member" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:type="locator" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MutualFundMember" xlink:type="locator" xlink:label="us-gaap_MutualFundMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:type="locator" xlink:label="us-gaap_InvestmentTypeCategorizationMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:type="locator" xlink:label="us-gaap_InvestmentTypeCategorizationMember_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentTypeAxis" xlink:type="locator" xlink:label="us-gaap_InvestmentTypeAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CaptiveInsuranceCollateralMember" xlink:type="locator" xlink:label="sgu_CaptiveInsuranceCollateralMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CollateralDomain" xlink:type="locator" xlink:label="us-gaap_CollateralDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CollateralDomain" xlink:type="locator" xlink:label="us-gaap_CollateralDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CollateralAxis" xlink:type="locator" xlink:label="us-gaap_CollateralAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:type="locator" xlink:label="us-gaap_FurnitureAndFixturesMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_TanksAndEquipmentMember" xlink:type="locator" xlink:label="sgu_TanksAndEquipmentMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_FleetAndOtherEquipmentMember" xlink:type="locator" xlink:label="sgu_FleetAndOtherEquipmentMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_BuildingAndLeaseholdImprovementsMember" xlink:type="locator" xlink:label="sgu_BuildingAndLeaseholdImprovementsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LandAndLandImprovementsMember" xlink:type="locator" xlink:label="us-gaap_LandAndLandImprovementsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:type="locator" xlink:label="srt_MinimumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:type="locator" xlink:label="srt_MaximumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:type="locator" xlink:label="srt_RangeMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:type="locator" xlink:label="srt_RangeMember_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:type="locator" xlink:label="srt_RangeAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_ScheduleOfSignificantAccountingPoliciesTable" xlink:type="locator" xlink:label="sgu_ScheduleOfSignificantAccountingPoliciesTable" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:type="locator" xlink:label="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="sgu_ScheduleOfSignificantAccountingPoliciesTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesTable" xlink:to="srt_RangeAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MaximumMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MinimumMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesTable" xlink:to="us-gaap_PropertyPlantAndEquipmentByTypeAxis" order="10200.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain_2" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain" order="10230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_LandAndLandImprovementsMember" order="10250.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="sgu_BuildingAndLeaseholdImprovementsMember" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="sgu_FleetAndOtherEquipmentMember" order="10290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="sgu_TanksAndEquipmentMember" order="10310.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_FurnitureAndFixturesMember" order="10330.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesTable" xlink:to="us-gaap_CollateralAxis" order="10340.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_CollateralAxis" xlink:to="us-gaap_CollateralDomain_2" order="10350.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_CollateralAxis" xlink:to="us-gaap_CollateralDomain" order="10370.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CollateralDomain" xlink:to="sgu_CaptiveInsuranceCollateralMember" order="10390.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesTable" xlink:to="us-gaap_InvestmentTypeAxis" order="10420.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_InvestmentTypeAxis" xlink:to="us-gaap_InvestmentTypeCategorizationMember_2" order="10430.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_InvestmentTypeAxis" xlink:to="us-gaap_InvestmentTypeCategorizationMember" order="10450.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_InvestmentTypeCategorizationMember" xlink:to="us-gaap_MutualFundMember" order="10470.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesTable" xlink:to="us-gaap_FairValueByFairValueHierarchyLevelAxis" order="10480.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2" order="10490.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" order="10510.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="us-gaap_FairValueInputsLevel1Member" order="10530.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesTable" xlink:to="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" order="10620.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_2" order="10630.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" order="10650.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="us-gaap_CustomerListsMember" order="10670.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="us-gaap_TradeNamesMember" order="10810.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesTable" xlink:to="us-gaap_FairValueByAssetClassAxis" order="10820.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_FairValueByAssetClassAxis" xlink:to="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_2" order="10830.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FairValueByAssetClassAxis" xlink:to="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" order="10850.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:to="us-gaap_GoodwillMember" order="10870.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:to="us-gaap_IndefinitelivedIntangibleAssetsMember" order="10890.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:to="us-gaap_PropertyPlantAndEquipmentMember" order="10910.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:to="sgu_OperatingLeaseRightUseOfAssetsMember" order="10930.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesTable" xlink:to="us-gaap_FairValueByLiabilityClassAxis" order="10940.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_FairValueByLiabilityClassAxis" xlink:to="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_2" order="10950.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FairValueByLiabilityClassAxis" xlink:to="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" order="10970.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:to="sgu_OperatingLeaseObligationsMember" order="10990.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesTable" xlink:to="us-gaap_SubsequentEventTypeAxis" order="11000.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_SubsequentEventTypeAxis" xlink:to="us-gaap_SubsequentEventTypeDomain_2" order="11010.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_SubsequentEventTypeAxis" xlink:to="us-gaap_SubsequentEventTypeDomain" order="11030.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventTypeDomain" xlink:to="us-gaap_SubsequentEventMember" order="11050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_OilAndGasPropertiesMember" order="11190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesTable" xlink:to="dei_LegalEntityAxis" order="11280.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="dei_LegalEntityAxis" xlink:to="dei_EntityDomain_2" order="11290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="dei_LegalEntityAxis" xlink:to="dei_EntityDomain" order="11310.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="dei_EntityDomain" xlink:to="sgu_FinancialProductsCorporationMember" order="11330.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesTable" xlink:to="srt_StatementScenarioAxis" order="11340.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_StatementScenarioAxis" xlink:to="srt_ScenarioUnspecifiedDomain_2" order="11350.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_StatementScenarioAxis" xlink:to="srt_ScenarioUnspecifiedDomain" order="11370.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ScenarioUnspecifiedDomain" xlink:to="srt_ScenarioForecastMember" order="11390.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesTable" xlink:to="us-gaap_IncomeStatementLocationAxis" order="11420.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="us-gaap_IncomeStatementLocationDomain_2" order="11430.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="us-gaap_IncomeStatementLocationDomain" order="11450.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementLocationDomain" xlink:to="sgu_OperatingCostsAndExpensesMember" order="11470.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesTable" xlink:to="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" order="11560.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:to="us-gaap_TypeOfAdoptionMember_2" order="11570.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:to="us-gaap_TypeOfAdoptionMember" order="11590.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TypeOfAdoptionMember" xlink:to="us-gaap_AccountingStandardsUpdate201602Member" order="11610.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesTable" xlink:to="us-gaap_DerivativeInstrumentRiskAxis" order="11660.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_DerivativeInstrumentRiskAxis" xlink:to="us-gaap_DerivativeContractTypeDomain_2" order="11670.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DerivativeInstrumentRiskAxis" xlink:to="us-gaap_DerivativeContractTypeDomain" order="11690.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativeContractTypeDomain" xlink:to="us-gaap_InterestRateSwapMember" order="11710.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="sgu_CashEquivalentsMaturityPeriod" order="11740.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" order="11780.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue" order="11820.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_RestrictedCashAndCashEquivalentsNoncurrent" order="11860.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentUsefulLife" order="11930.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtSecurities" order="12260.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="sgu_MutualFundMeasurementInvestmentAtNetAssets" order="12300.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_NumberOfReportableSegments" order="12370.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_GoodwillImpairmentLoss" order="12430.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="sgu_MinimumPercentageOfLikelihoodOnGoodwillImpairment" order="12490.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_FiniteLivedIntangibleAssetUsefulLife" order="12580.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_AssetsHeldForSaleNotPartOfDisposalGroup" order="12720.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_GainLossOnDispositionOfAssets1" order="12800.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="sgu_LiabilitiesHeldForSaleNotPartOfDisposalGroup" order="12820.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_OtherNonoperatingIncomeExpense" order="12870.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_ProceedsFromDivestitureOfBusinesses" order="12910.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="sgu_RecognitionOfUnmotizedDeferredLiabilities" order="12950.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_OtherExpenses" order="12990.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_AdvertisingExpense" order="13060.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_IncomeTaxExaminationLikelihoodOfUnfavorableSettlement" order="13150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="sgu_AdditionalPaymentObligatedToPayIfDegreeDaysExceedTenYearAverage" order="13200.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="sgu_RightToReceivePaymentUnderWeatherHedgeContract" order="13300.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="sgu_DerivativeMaximumPayoutUnderWeatherHedgeContract" order="13400.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_DerivativeGainLossOnDerivativeNet" order="13500.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_OperatingLeaseRightOfUseAsset" order="13630.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_OperatingLeaseLiabilityCurrent" order="13650.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_OperatingLeaseLiabilityNoncurrent" order="13670.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_ScheduleOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_DerivativeNotionalAmount" order="13720.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureRevenueRecognitionSummaryOfDisaggregationOfRevenueByMajorSourcesDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureRevenueRecognitionSummaryOfDisaggregationOfRevenueByMajorSourcesDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureRevenueRecognitionSummaryOfDisaggregationOfRevenueByMajorSourcesDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:type="locator" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_InstallationAndServicesMember" xlink:type="locator" xlink:label="sgu_InstallationAndServicesMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_BillableCallServicesMember" xlink:type="locator" xlink:label="sgu_BillableCallServicesMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_EquipmentMaintenanceServiceContractsMember" xlink:type="locator" xlink:label="sgu_EquipmentMaintenanceServiceContractsMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_EquipmentInstallationsMember" xlink:type="locator" xlink:label="sgu_EquipmentInstallationsMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_PetroleumProductsMember" xlink:type="locator" xlink:label="sgu_PetroleumProductsMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MotorFuelAndOtherPetroleumProductsMember" xlink:type="locator" xlink:label="sgu_MotorFuelAndOtherPetroleumProductsMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_HomeHeatingOilAndPropaneMember" xlink:type="locator" xlink:label="sgu_HomeHeatingOilAndPropaneMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:type="locator" xlink:label="srt_ProductsAndServicesDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis" xlink:type="locator" xlink:label="srt_ProductOrServiceAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:type="locator" xlink:label="us-gaap_DisaggregationOfRevenueTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:type="locator" xlink:label="us-gaap_DisaggregationOfRevenueLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DisaggregationOfRevenueLineItems" xlink:to="us-gaap_DisaggregationOfRevenueTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DisaggregationOfRevenueTable" xlink:to="srt_ProductOrServiceAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_ProductOrServiceAxis" xlink:to="srt_ProductsAndServicesDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain" xlink:to="sgu_HomeHeatingOilAndPropaneMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain" xlink:to="sgu_MotorFuelAndOtherPetroleumProductsMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain" xlink:to="sgu_PetroleumProductsMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain" xlink:to="sgu_EquipmentInstallationsMember" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain" xlink:to="sgu_EquipmentMaintenanceServiceContractsMember" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain" xlink:to="sgu_BillableCallServicesMember" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain" xlink:to="sgu_InstallationAndServicesMember" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DisaggregationOfRevenueLineItems" xlink:to="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" order="10240.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureRevenueRecognitionAdditionalInformationDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureRevenueRecognitionAdditionalInformationDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureRevenueRecognitionAdditionalInformationDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerLiabilityRevenueRecognized" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerLiability" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerLiability" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_ContractLiabilitiesRecognitionServiceContractPeriod" xlink:type="locator" xlink:label="sgu_ContractLiabilitiesRecognitionServiceContractPeriod" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_PercentageOfCustomersTakeAdvantageOfSmartPayBudgetPaymentPlan" xlink:type="locator" xlink:label="sgu_PercentageOfCustomersTakeAdvantageOfSmartPayBudgetPaymentPlan" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalizedContractCostImpairmentLoss" xlink:type="locator" xlink:label="us-gaap_CapitalizedContractCostImpairmentLoss" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalizedContractCostAmortization" xlink:type="locator" xlink:label="us-gaap_CapitalizedContractCostAmortization" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalizedContractCostNetNoncurrent" xlink:type="locator" xlink:label="us-gaap_CapitalizedContractCostNetNoncurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalizedContractCostNetCurrent" xlink:type="locator" xlink:label="us-gaap_CapitalizedContractCostNetCurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalizedContractCostAmortizationPeriod" xlink:type="locator" xlink:label="us-gaap_CapitalizedContractCostAmortizationPeriod" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenuePracticalExpedientIncrementalCostOfObtainingContract" xlink:type="locator" xlink:label="us-gaap_RevenuePracticalExpedientIncrementalCostOfObtainingContract" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CustomerPaymentTerms" xlink:type="locator" xlink:label="sgu_CustomerPaymentTerms" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_RevenueFromServiceContractsPeriodOfRecognition" xlink:type="locator" xlink:label="sgu_RevenueFromServiceContractsPeriodOfRecognition" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_PercentageOfCustomersReceivingDeliveriesBasedOnPrevailingWeatherConditions" xlink:type="locator" xlink:label="sgu_PercentageOfCustomersReceivingDeliveriesBasedOnPrevailingWeatherConditions" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherNoncurrentAssetsMember" xlink:type="locator" xlink:label="us-gaap_OtherNoncurrentAssetsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember" xlink:type="locator" xlink:label="us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DeliveryAndBranchExpensesMember" xlink:type="locator" xlink:label="sgu_DeliveryAndBranchExpensesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_ResidentialCustomersMember" xlink:type="locator" xlink:label="sgu_ResidentialCustomersMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:type="locator" xlink:label="srt_MinimumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:type="locator" xlink:label="srt_MaximumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:type="locator" xlink:label="srt_RangeMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:type="locator" xlink:label="srt_RangeAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_EquipmentMaintenanceServiceContractsMember" xlink:type="locator" xlink:label="sgu_EquipmentMaintenanceServiceContractsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:type="locator" xlink:label="srt_ProductsAndServicesDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis" xlink:type="locator" xlink:label="srt_ProductOrServiceAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_ResidentialAndCommercialHomeHeatingOilCustomersMember" xlink:type="locator" xlink:label="sgu_ResidentialAndCommercialHomeHeatingOilCustomersMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:type="locator" xlink:label="srt_NameOfMajorCustomerDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:type="locator" xlink:label="srt_NameOfMajorCustomerDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MajorCustomersAxis" xlink:type="locator" xlink:label="srt_MajorCustomersAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_RevenueRecognitionTable" xlink:type="locator" xlink:label="sgu_RevenueRecognitionTable" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_RevenueRecognitionLineItems" xlink:type="locator" xlink:label="sgu_RevenueRecognitionLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="sgu_RevenueRecognitionLineItems" xlink:to="sgu_RevenueRecognitionTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_RevenueRecognitionTable" xlink:to="srt_MajorCustomersAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_MajorCustomersAxis" xlink:to="srt_NameOfMajorCustomerDomain_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_MajorCustomersAxis" xlink:to="srt_NameOfMajorCustomerDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_NameOfMajorCustomerDomain" xlink:to="sgu_ResidentialAndCommercialHomeHeatingOilCustomersMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_RevenueRecognitionTable" xlink:to="srt_ProductOrServiceAxis" order="10100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_ProductOrServiceAxis" xlink:to="srt_ProductsAndServicesDomain" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain" xlink:to="sgu_EquipmentMaintenanceServiceContractsMember" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_RevenueRecognitionTable" xlink:to="srt_RangeAxis" order="10160.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MaximumMember" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MinimumMember" order="10230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_NameOfMajorCustomerDomain" xlink:to="sgu_ResidentialCustomersMember" order="10290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_RevenueRecognitionTable" xlink:to="us-gaap_IncomeStatementLocationAxis" order="10300.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="us-gaap_IncomeStatementLocationDomain" order="10330.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementLocationDomain" xlink:to="sgu_DeliveryAndBranchExpensesMember" order="10350.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_RevenueRecognitionTable" xlink:to="us-gaap_BalanceSheetLocationAxis" order="10360.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_BalanceSheetLocationAxis" xlink:to="us-gaap_BalanceSheetLocationDomain_2" order="10370.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BalanceSheetLocationAxis" xlink:to="us-gaap_BalanceSheetLocationDomain" order="10390.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember" order="10410.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="us-gaap_OtherNoncurrentAssetsMember" order="10430.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_RevenueRecognitionLineItems" xlink:to="sgu_PercentageOfCustomersReceivingDeliveriesBasedOnPrevailingWeatherConditions" order="10600.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_RevenueRecognitionLineItems" xlink:to="sgu_RevenueFromServiceContractsPeriodOfRecognition" order="10650.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_RevenueRecognitionLineItems" xlink:to="sgu_CustomerPaymentTerms" order="10700.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_RevenueRecognitionLineItems" xlink:to="us-gaap_RevenuePracticalExpedientIncrementalCostOfObtainingContract" order="10750.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_RevenueRecognitionLineItems" xlink:to="us-gaap_CapitalizedContractCostAmortizationPeriod" order="10790.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_RevenueRecognitionLineItems" xlink:to="us-gaap_CapitalizedContractCostNetCurrent" order="10830.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_RevenueRecognitionLineItems" xlink:to="us-gaap_CapitalizedContractCostNetNoncurrent" order="10870.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_RevenueRecognitionLineItems" xlink:to="us-gaap_CapitalizedContractCostAmortization" order="10910.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_RevenueRecognitionLineItems" xlink:to="us-gaap_CapitalizedContractCostImpairmentLoss" order="10950.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_RevenueRecognitionLineItems" xlink:to="sgu_PercentageOfCustomersTakeAdvantageOfSmartPayBudgetPaymentPlan" order="11020.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_RevenueRecognitionLineItems" xlink:to="sgu_ContractLiabilitiesRecognitionServiceContractPeriod" order="11060.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_RevenueRecognitionLineItems" xlink:to="us-gaap_ContractWithCustomerLiability" order="11100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_RevenueRecognitionLineItems" xlink:to="us-gaap_ContractWithCustomerLiabilityRevenueRecognized" order="11140.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureCommonUnitRepurchasePlansAndRetirementAdditionalInformationDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureCommonUnitRepurchasePlansAndRetirementAdditionalInformationDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureCommonUnitRepurchasePlansAndRetirementAdditionalInformationDetail">
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MinimumFixedChargeCoverageRatioForDistributionsToUnitholdersOrRepurchaseCommonUnits" xlink:type="locator" xlink:label="sgu_MinimumFixedChargeCoverageRatioForDistributionsToUnitholdersOrRepurchaseCommonUnits" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MinimumPercentageOfBorrowingCapacityToPayAnyDistributionsToUnitholdersOrRepurchaseCommonUnits" xlink:type="locator" xlink:label="sgu_MinimumPercentageOfBorrowingCapacityToPayAnyDistributionsToUnitholdersOrRepurchaseCommonUnits" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_AvailabilityRequiredToPayDistributionsOrRepurchaseCommonUnits" xlink:type="locator" xlink:label="sgu_AvailabilityRequiredToPayDistributionsOrRepurchaseCommonUnits" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" xlink:type="locator" xlink:label="us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:type="locator" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_FifthAmendmentMember" xlink:type="locator" xlink:label="sgu_FifthAmendmentMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityLenderDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityAxis" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventMember" xlink:type="locator" xlink:label="us-gaap_SubsequentEventMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:type="locator" xlink:label="us-gaap_SubsequentEventTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:type="locator" xlink:label="us-gaap_SubsequentEventTypeAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_PubliclyAnnouncedPlansOrProgramsAsPartOfCommonStockRepurchaseProgramMember" xlink:type="locator" xlink:label="sgu_PubliclyAnnouncedPlansOrProgramsAsPartOfCommonStockRepurchaseProgramMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CommonStockRepurchaseProgramUnderPrivatelyNegotiatedMember" xlink:type="locator" xlink:label="sgu_CommonStockRepurchaseProgramUnderPrivatelyNegotiatedMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CommonStockRepurchaseProgramUnderOpenMarketMember" xlink:type="locator" xlink:label="sgu_CommonStockRepurchaseProgramUnderOpenMarketMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CommonStockRepurchaseProgramMember" xlink:type="locator" xlink:label="sgu_CommonStockRepurchaseProgramMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain" xlink:type="locator" xlink:label="us-gaap_ShareRepurchaseProgramDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain" xlink:type="locator" xlink:label="us-gaap_ShareRepurchaseProgramDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramAxis" xlink:type="locator" xlink:label="us-gaap_ShareRepurchaseProgramAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfCapitalUnitsTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfCapitalUnitsTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalUnitLineItems" xlink:type="locator" xlink:label="us-gaap_CapitalUnitLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_CapitalUnitLineItems" xlink:to="us-gaap_ScheduleOfCapitalUnitsTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfCapitalUnitsTable" xlink:to="us-gaap_ShareRepurchaseProgramAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ShareRepurchaseProgramAxis" xlink:to="us-gaap_ShareRepurchaseProgramDomain_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ShareRepurchaseProgramAxis" xlink:to="us-gaap_ShareRepurchaseProgramDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareRepurchaseProgramDomain" xlink:to="sgu_CommonStockRepurchaseProgramMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareRepurchaseProgramDomain" xlink:to="sgu_CommonStockRepurchaseProgramUnderOpenMarketMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareRepurchaseProgramDomain" xlink:to="sgu_CommonStockRepurchaseProgramUnderPrivatelyNegotiatedMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareRepurchaseProgramDomain" xlink:to="sgu_PubliclyAnnouncedPlansOrProgramsAsPartOfCommonStockRepurchaseProgramMember" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfCapitalUnitsTable" xlink:to="us-gaap_SubsequentEventTypeAxis" order="10180.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_SubsequentEventTypeAxis" xlink:to="us-gaap_SubsequentEventTypeDomain" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventTypeDomain" xlink:to="us-gaap_SubsequentEventMember" order="10230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfCapitalUnitsTable" xlink:to="us-gaap_LineOfCreditFacilityAxis" order="10240.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_LineOfCreditFacilityAxis" xlink:to="us-gaap_LineOfCreditFacilityLenderDomain" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLenderDomain" xlink:to="sgu_FifthAmendmentMember" order="10290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CapitalUnitLineItems" xlink:to="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" order="10380.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CapitalUnitLineItems" xlink:to="us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" order="10440.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CapitalUnitLineItems" xlink:to="sgu_AvailabilityRequiredToPayDistributionsOrRepurchaseCommonUnits" order="10830.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CapitalUnitLineItems" xlink:to="sgu_MinimumPercentageOfBorrowingCapacityToPayAnyDistributionsToUnitholdersOrRepurchaseCommonUnits" order="10850.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CapitalUnitLineItems" xlink:to="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" order="10870.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CapitalUnitLineItems" xlink:to="sgu_MinimumFixedChargeCoverageRatioForDistributionsToUnitholdersOrRepurchaseCommonUnits" order="10890.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureCommonUnitRepurchasePlansAndRetirementCompanySRepurchaseActivitiesDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureCommonUnitRepurchasePlansAndRetirementCompanySRepurchaseActivitiesDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureCommonUnitRepurchasePlansAndRetirementCompanySRepurchaseActivitiesDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased" xlink:type="locator" xlink:label="us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_AveragePricePaidPerUnit" xlink:type="locator" xlink:label="sgu_AveragePricePaidPerUnit" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:type="locator" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventMember" xlink:type="locator" xlink:label="us-gaap_SubsequentEventMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:type="locator" xlink:label="us-gaap_SubsequentEventTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:type="locator" xlink:label="us-gaap_SubsequentEventTypeAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_PubliclyAnnouncedPlansOrProgramsAsPartOfCommonStockRepurchaseProgramMember" xlink:type="locator" xlink:label="sgu_PubliclyAnnouncedPlansOrProgramsAsPartOfCommonStockRepurchaseProgramMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CommonStockRepurchaseProgramMember" xlink:type="locator" xlink:label="sgu_CommonStockRepurchaseProgramMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain" xlink:type="locator" xlink:label="us-gaap_ShareRepurchaseProgramDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramAxis" xlink:type="locator" xlink:label="us-gaap_ShareRepurchaseProgramAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfCapitalUnitsTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfCapitalUnitsTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalUnitLineItems" xlink:type="locator" xlink:label="us-gaap_CapitalUnitLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_CapitalUnitLineItems" xlink:to="us-gaap_ScheduleOfCapitalUnitsTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfCapitalUnitsTable" xlink:to="us-gaap_ShareRepurchaseProgramAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ShareRepurchaseProgramAxis" xlink:to="us-gaap_ShareRepurchaseProgramDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareRepurchaseProgramDomain" xlink:to="sgu_CommonStockRepurchaseProgramMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareRepurchaseProgramDomain" xlink:to="sgu_PubliclyAnnouncedPlansOrProgramsAsPartOfCommonStockRepurchaseProgramMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfCapitalUnitsTable" xlink:to="us-gaap_SubsequentEventTypeAxis" order="10160.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_SubsequentEventTypeAxis" xlink:to="us-gaap_SubsequentEventTypeDomain" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventTypeDomain" xlink:to="us-gaap_SubsequentEventMember" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CapitalUnitLineItems" xlink:to="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" order="10260.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CapitalUnitLineItems" xlink:to="sgu_AveragePricePaidPerUnit" order="10480.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CapitalUnitLineItems" xlink:to="us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased" order="10920.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureCommonUnitRepurchasePlansAndRetirementCompanySRepurchaseActivitiesParentheticalDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureCommonUnitRepurchasePlansAndRetirementCompanySRepurchaseActivitiesParentheticalDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureCommonUnitRepurchasePlansAndRetirementCompanySRepurchaseActivitiesParentheticalDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodValue" xlink:type="locator" xlink:label="us-gaap_StockRepurchasedDuringPeriodValue" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" xlink:type="locator" xlink:label="us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodShares" xlink:type="locator" xlink:label="us-gaap_StockRepurchasedDuringPeriodShares" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MoabPartnersLPMember" xlink:type="locator" xlink:label="sgu_MoabPartnersLPMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:type="locator" xlink:label="us-gaap_RelatedPartyDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:type="locator" xlink:label="us-gaap_RelatedPartyDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_UnitPurchaseAgreementMember" xlink:type="locator" xlink:label="sgu_UnitPurchaseAgreementMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventMember" xlink:type="locator" xlink:label="us-gaap_SubsequentEventMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:type="locator" xlink:label="us-gaap_SubsequentEventTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:type="locator" xlink:label="us-gaap_SubsequentEventTypeAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CommonStockRepurchaseProgramUnderPrivatelyNegotiatedMember" xlink:type="locator" xlink:label="sgu_CommonStockRepurchaseProgramUnderPrivatelyNegotiatedMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CommonStockRepurchaseProgramUnderOpenMarketMember" xlink:type="locator" xlink:label="sgu_CommonStockRepurchaseProgramUnderOpenMarketMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_PrivateTransactionMember" xlink:type="locator" xlink:label="sgu_PrivateTransactionMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain" xlink:type="locator" xlink:label="us-gaap_ShareRepurchaseProgramDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramAxis" xlink:type="locator" xlink:label="us-gaap_ShareRepurchaseProgramAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfCapitalUnitsTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfCapitalUnitsTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalUnitLineItems" xlink:type="locator" xlink:label="us-gaap_CapitalUnitLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_CapitalUnitLineItems" xlink:to="us-gaap_ScheduleOfCapitalUnitsTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfCapitalUnitsTable" xlink:to="us-gaap_ShareRepurchaseProgramAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ShareRepurchaseProgramAxis" xlink:to="us-gaap_ShareRepurchaseProgramDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareRepurchaseProgramDomain" xlink:to="sgu_PrivateTransactionMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareRepurchaseProgramDomain" xlink:to="sgu_CommonStockRepurchaseProgramUnderOpenMarketMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareRepurchaseProgramDomain" xlink:to="sgu_CommonStockRepurchaseProgramUnderPrivatelyNegotiatedMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfCapitalUnitsTable" xlink:to="us-gaap_SubsequentEventTypeAxis" order="10140.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_SubsequentEventTypeAxis" xlink:to="us-gaap_SubsequentEventTypeDomain" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventTypeDomain" xlink:to="us-gaap_SubsequentEventMember" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareRepurchaseProgramDomain" xlink:to="sgu_UnitPurchaseAgreementMember" order="10330.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfCapitalUnitsTable" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" order="10360.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain_2" order="10370.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain" order="10390.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="sgu_MoabPartnersLPMember" order="10410.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CapitalUnitLineItems" xlink:to="us-gaap_StockRepurchasedDuringPeriodShares" order="10460.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CapitalUnitLineItems" xlink:to="us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" order="10520.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CapitalUnitLineItems" xlink:to="us-gaap_StockRepurchasedDuringPeriodValue" order="10870.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureCaptiveInsuranceCollateralScheduleOfCaptiveInsuranceCollateralToBeAvailableForSaleInvestmentsDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureCaptiveInsuranceCollateralScheduleOfCaptiveInsuranceCollateralToBeAvailableForSaleInvestmentsDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureCaptiveInsuranceCollateralScheduleOfCaptiveInsuranceCollateralToBeAvailableForSaleInvestmentsDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_ForeignBondsAndNotesMember" xlink:type="locator" xlink:label="sgu_ForeignBondsAndNotesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember" xlink:type="locator" xlink:label="us-gaap_CorporateDebtSecuritiesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember" xlink:type="locator" xlink:label="us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CashAndReceivablesMember" xlink:type="locator" xlink:label="sgu_CashAndReceivablesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:type="locator" xlink:label="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:type="locator" xlink:label="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:type="locator" xlink:label="us-gaap_FinancialInstrumentAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable" xlink:type="locator" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:type="locator" xlink:label="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleTable" order="10040.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleTable" xlink:to="us-gaap_FinancialInstrumentAxis" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_FinancialInstrumentAxis" xlink:to="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_2" order="10080.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FinancialInstrumentAxis" xlink:to="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" order="10100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="sgu_CashAndReceivablesMember" order="10120.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember" order="10140.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="us-gaap_CorporateDebtSecuritiesMember" order="10160.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="sgu_ForeignBondsAndNotesMember" order="10180.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" order="10330.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" order="10450.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" order="10570.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtSecurities" order="10690.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureDerivativesAndHedgingDisclosuresAndFairValueMeasurementsAdditionalInformationDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureDerivativesAndHedgingDisclosuresAndFairValueMeasurementsAdditionalInformationDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureDerivativesAndHedgingDisclosuresAndFairValueMeasurementsAdditionalInformationDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeAmountOfHedgedItem" xlink:type="locator" xlink:label="us-gaap_DerivativeAmountOfHedgedItem" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashCollateralForBorrowedSecurities" xlink:type="locator" xlink:label="us-gaap_CashCollateralForBorrowedSecurities" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PercentageOfDebtHedgedByInterestRateDerivatives" xlink:type="locator" xlink:label="us-gaap_PercentageOfDebtHedgedByInterestRateDerivatives" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeNet" xlink:type="locator" xlink:label="us-gaap_DerivativeFairValueOfDerivativeNet" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeNotionalAmount" xlink:type="locator" xlink:label="us-gaap_DerivativeNotionalAmount" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeNonmonetaryNotionalAmountVolume" xlink:type="locator" xlink:label="us-gaap_DerivativeNonmonetaryNotionalAmountVolume" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember" xlink:type="locator" xlink:label="us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRateSwapMember" xlink:type="locator" xlink:label="us-gaap_InterestRateSwapMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:type="locator" xlink:label="us-gaap_DerivativeContractTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:type="locator" xlink:label="us-gaap_DerivativeInstrumentRiskAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:type="locator" xlink:label="srt_MinimumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:type="locator" xlink:label="srt_MaximumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:type="locator" xlink:label="srt_RangeMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:type="locator" xlink:label="srt_RangeAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SyntheticOilMember" xlink:type="locator" xlink:label="srt_SyntheticOilMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TypeOfReserveDomain" xlink:type="locator" xlink:label="srt_TypeOfReserveDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TypeOfReserveDomain" xlink:type="locator" xlink:label="srt_TypeOfReserveDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ReserveQuantitiesByTypeOfReserveAxis" xlink:type="locator" xlink:label="srt_ReserveQuantitiesByTypeOfReserveAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PutOptionMember" xlink:type="locator" xlink:label="us-gaap_PutOptionMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CallOptionMember" xlink:type="locator" xlink:label="us-gaap_CallOptionMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OptionIndexedToIssuersEquityTypeDomain" xlink:type="locator" xlink:label="us-gaap_OptionIndexedToIssuersEquityTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OptionIndexedToIssuersEquityTypeDomain" xlink:type="locator" xlink:label="us-gaap_OptionIndexedToIssuersEquityTypeDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OptionIndexedToIssuersEquityTypeAxis" xlink:type="locator" xlink:label="us-gaap_OptionIndexedToIssuersEquityTypeAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongMember" xlink:type="locator" xlink:label="us-gaap_LongMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortMember" xlink:type="locator" xlink:label="us-gaap_ShortMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PositionDomain" xlink:type="locator" xlink:label="us-gaap_PositionDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PositionDomain" xlink:type="locator" xlink:label="us-gaap_PositionDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PositionAxis" xlink:type="locator" xlink:label="us-gaap_PositionAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_InternalFuelUsageCallAndSwapContractMember" xlink:type="locator" xlink:label="sgu_InternalFuelUsageCallAndSwapContractMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FutureMember" xlink:type="locator" xlink:label="us-gaap_FutureMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_SwapContractOneMember" xlink:type="locator" xlink:label="sgu_SwapContractOneMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:type="locator" xlink:label="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:type="locator" xlink:label="us-gaap_FinancialInstrumentAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable" xlink:type="locator" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems" xlink:type="locator" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems" xlink:to="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable" xlink:to="us-gaap_FinancialInstrumentAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FinancialInstrumentAxis" xlink:to="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="sgu_SwapContractOneMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="us-gaap_FutureMember" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="sgu_InternalFuelUsageCallAndSwapContractMember" order="10370.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable" xlink:to="us-gaap_PositionAxis" order="10440.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_PositionAxis" xlink:to="us-gaap_PositionDomain_2" order="10450.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_PositionAxis" xlink:to="us-gaap_PositionDomain" order="10470.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PositionDomain" xlink:to="us-gaap_ShortMember" order="10490.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PositionDomain" xlink:to="us-gaap_LongMember" order="10510.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable" xlink:to="us-gaap_OptionIndexedToIssuersEquityTypeAxis" order="10720.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_OptionIndexedToIssuersEquityTypeAxis" xlink:to="us-gaap_OptionIndexedToIssuersEquityTypeDomain_2" order="10730.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_OptionIndexedToIssuersEquityTypeAxis" xlink:to="us-gaap_OptionIndexedToIssuersEquityTypeDomain" order="10750.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OptionIndexedToIssuersEquityTypeDomain" xlink:to="us-gaap_CallOptionMember" order="10770.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OptionIndexedToIssuersEquityTypeDomain" xlink:to="us-gaap_PutOptionMember" order="10830.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable" xlink:to="srt_ReserveQuantitiesByTypeOfReserveAxis" order="10940.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_ReserveQuantitiesByTypeOfReserveAxis" xlink:to="srt_TypeOfReserveDomain_2" order="10950.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_ReserveQuantitiesByTypeOfReserveAxis" xlink:to="srt_TypeOfReserveDomain" order="10970.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_TypeOfReserveDomain" xlink:to="srt_SyntheticOilMember" order="10990.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable" xlink:to="srt_RangeAxis" order="11040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="11070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MaximumMember" order="11090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MinimumMember" order="11110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable" xlink:to="us-gaap_DerivativeInstrumentRiskAxis" order="11120.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DerivativeInstrumentRiskAxis" xlink:to="us-gaap_DerivativeContractTypeDomain" order="11150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativeContractTypeDomain" xlink:to="us-gaap_InterestRateSwapMember" order="11170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable" xlink:to="us-gaap_BalanceSheetLocationAxis" order="11260.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BalanceSheetLocationAxis" xlink:to="us-gaap_BalanceSheetLocationDomain" order="11290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember" order="11310.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems" xlink:to="us-gaap_DerivativeNonmonetaryNotionalAmountVolume" order="11340.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems" xlink:to="us-gaap_DerivativeNotionalAmount" order="11380.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems" xlink:to="us-gaap_DerivativeFairValueOfDerivativeNet" order="11420.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems" xlink:to="us-gaap_PercentageOfDebtHedgedByInterestRateDerivatives" order="12470.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems" xlink:to="us-gaap_CashCollateralForBorrowedSecurities" order="12580.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems" xlink:to="us-gaap_DerivativeAmountOfHedgedItem" order="12600.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureDerivativesAndHedgingDisclosuresAndFairValueMeasurementsCompanySCommodityFinancialAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureDerivativesAndHedgingDisclosuresAndFairValueMeasurementsCompanySCommodityFinancialAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureDerivativesAndHedgingDisclosuresAndFairValueMeasurementsCompanySCommodityFinancialAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue" xlink:type="locator" xlink:label="us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAssetAtFairValue" xlink:type="locator" xlink:label="us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAssetAtFairValue" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DeferredChargesAndOtherAssetsNetAndOtherLongTermLiabilitiesNetMember" xlink:type="locator" xlink:label="sgu_DeferredChargesAndOtherAssetsNetAndOtherLongTermLiabilitiesNetMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DerivativeFairValueOfDerivativeLiabilityMember" xlink:type="locator" xlink:label="sgu_DerivativeFairValueOfDerivativeLiabilityMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommodityContractMember" xlink:type="locator" xlink:label="us-gaap_CommodityContractMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:type="locator" xlink:label="us-gaap_DerivativeContractTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:type="locator" xlink:label="us-gaap_DerivativeInstrumentRiskAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NondesignatedMember" xlink:type="locator" xlink:label="us-gaap_NondesignatedMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:type="locator" xlink:label="us-gaap_HedgingDesignationDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:type="locator" xlink:label="us-gaap_HedgingDesignationDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationAxis" xlink:type="locator" xlink:label="us-gaap_HedgingDesignationAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:type="locator" xlink:label="us-gaap_FairValueInputsLevel2Member" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:type="locator" xlink:label="us-gaap_FairValueInputsLevel1Member" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:type="locator" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementsRecurringMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:type="locator" xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:type="locator" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:type="locator" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="us-gaap_FairValueByMeasurementFrequencyAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_FairValueByMeasurementFrequencyAxis" xlink:to="us-gaap_FairValueMeasurementFrequencyDomain_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FairValueByMeasurementFrequencyAxis" xlink:to="us-gaap_FairValueMeasurementFrequencyDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueMeasurementFrequencyDomain" xlink:to="us-gaap_FairValueMeasurementsRecurringMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="us-gaap_FairValueByFairValueHierarchyLevelAxis" order="10100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="us-gaap_FairValueInputsLevel1Member" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="us-gaap_FairValueInputsLevel2Member" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="us-gaap_HedgingDesignationAxis" order="10180.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_HedgingDesignationAxis" xlink:to="us-gaap_HedgingDesignationDomain_2" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_HedgingDesignationAxis" xlink:to="us-gaap_HedgingDesignationDomain" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_HedgingDesignationDomain" xlink:to="us-gaap_NondesignatedMember" order="10230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="us-gaap_DerivativeInstrumentRiskAxis" order="10240.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DerivativeInstrumentRiskAxis" xlink:to="us-gaap_DerivativeContractTypeDomain" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativeContractTypeDomain" xlink:to="us-gaap_CommodityContractMember" order="10290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="us-gaap_BalanceSheetLocationAxis" order="10300.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BalanceSheetLocationAxis" xlink:to="us-gaap_BalanceSheetLocationDomain" order="10330.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="sgu_DerivativeFairValueOfDerivativeLiabilityMember" order="10350.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="sgu_DeferredChargesAndOtherAssetsNetAndOtherLongTermLiabilitiesNetMember" order="10370.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAssetAtFairValue" order="10520.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue" order="10820.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureDerivativesAndHedgingDisclosuresAndFairValueMeasurementsOffsettingOfFinancialAssetsLiabilitiesAndDerivativeAssetsLiabilitiesDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureDerivativesAndHedgingDisclosuresAndFairValueMeasurementsOffsettingOfFinancialAssetsLiabilitiesAndDerivativeAssetsLiabilitiesDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureDerivativesAndHedgingDisclosuresAndFairValueMeasurementsOffsettingOfFinancialAssetsLiabilitiesAndDerivativeAssetsLiabilitiesDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeNet" xlink:type="locator" xlink:label="us-gaap_DerivativeFairValueOfDerivativeNet" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CashCollateralReceivedFromNotOffsetAgainstDerivativeAssetsAndLiabilities" xlink:type="locator" xlink:label="sgu_CashCollateralReceivedFromNotOffsetAgainstDerivativeAssetsAndLiabilities" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DerivativeFairValueGrossAmountNotOffsetFinancialInstrumentsNet" xlink:type="locator" xlink:label="sgu_DerivativeFairValueGrossAmountNotOffsetFinancialInstrumentsNet" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet" xlink:type="locator" xlink:label="us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet" xlink:type="locator" xlink:label="us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeAssetAmountNotOffsetAgainstCollateral" xlink:type="locator" xlink:label="us-gaap_DerivativeFairValueOfDerivativeAssetAmountNotOffsetAgainstCollateral" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountOffsetAgainstCollateral" xlink:type="locator" xlink:label="us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountOffsetAgainstCollateral" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeCollateralRightToReclaimSecurities" xlink:type="locator" xlink:label="us-gaap_DerivativeCollateralRightToReclaimSecurities" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeCollateralRightToReclaimCash" xlink:type="locator" xlink:label="us-gaap_DerivativeCollateralRightToReclaimCash" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLiabilitiesNoncurrent" xlink:type="locator" xlink:label="us-gaap_DerivativeLiabilitiesNoncurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLiabilitiesCurrent" xlink:type="locator" xlink:label="us-gaap_DerivativeLiabilitiesCurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:type="locator" xlink:label="us-gaap_DerivativeFairValueOfDerivativeLiability" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLiabilityFairValueGrossAsset" xlink:type="locator" xlink:label="us-gaap_DerivativeLiabilityFairValueGrossAsset" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeAssetAmountOffsetAgainstCollateral" xlink:type="locator" xlink:label="us-gaap_DerivativeFairValueOfDerivativeAssetAmountOffsetAgainstCollateral" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeCollateralObligationToReturnCash" xlink:type="locator" xlink:label="us-gaap_DerivativeCollateralObligationToReturnCash" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeCollateralObligationToReturnSecurities" xlink:type="locator" xlink:label="us-gaap_DerivativeCollateralObligationToReturnSecurities" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeAssetsNoncurrent" xlink:type="locator" xlink:label="us-gaap_DerivativeAssetsNoncurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeAssetFairValueGrossLiability" xlink:type="locator" xlink:label="us-gaap_DerivativeAssetFairValueGrossLiability" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset" xlink:type="locator" xlink:label="us-gaap_DerivativeFairValueOfDerivativeAsset" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherNoncurrentLiabilitiesMember" xlink:type="locator" xlink:label="us-gaap_OtherNoncurrentLiabilitiesMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DerivativeFairValueOfDerivativeLiabilityMember" xlink:type="locator" xlink:label="sgu_DerivativeFairValueOfDerivativeLiabilityMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_LongTermDerivativeAssetsMember" xlink:type="locator" xlink:label="sgu_LongTermDerivativeAssetsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_SubjectToMasterNettingArrangementMember" xlink:type="locator" xlink:label="sgu_SubjectToMasterNettingArrangementMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:type="locator" xlink:label="us-gaap_DerivativeContractTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:type="locator" xlink:label="us-gaap_DerivativeInstrumentRiskAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsTable" xlink:type="locator" xlink:label="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsTable" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:type="locator" xlink:label="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsTable" order="10180.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsTable" xlink:to="us-gaap_DerivativeInstrumentRiskAxis" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DerivativeInstrumentRiskAxis" xlink:to="us-gaap_DerivativeContractTypeDomain" order="10240.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativeContractTypeDomain" xlink:to="sgu_SubjectToMasterNettingArrangementMember" order="10260.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsTable" xlink:to="us-gaap_BalanceSheetLocationAxis" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BalanceSheetLocationAxis" xlink:to="us-gaap_BalanceSheetLocationDomain" order="10300.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="sgu_LongTermDerivativeAssetsMember" order="10320.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="sgu_DerivativeFairValueOfDerivativeLiabilityMember" order="10460.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="us-gaap_OtherNoncurrentLiabilitiesMember" order="10480.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="us-gaap_DerivativeFairValueOfDerivativeAsset" order="10610.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="us-gaap_DerivativeAssetFairValueGrossLiability" order="10650.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="us-gaap_DerivativeAssetsNoncurrent" order="10690.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="us-gaap_DerivativeCollateralObligationToReturnSecurities" order="10730.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="us-gaap_DerivativeCollateralObligationToReturnCash" order="10770.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="us-gaap_DerivativeFairValueOfDerivativeAssetAmountOffsetAgainstCollateral" order="10810.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="us-gaap_DerivativeLiabilityFairValueGrossAsset" order="10880.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="us-gaap_DerivativeFairValueOfDerivativeLiability" order="10960.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="us-gaap_DerivativeLiabilitiesCurrent" order="11040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="us-gaap_DerivativeLiabilitiesNoncurrent" order="11060.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="us-gaap_DerivativeCollateralRightToReclaimCash" order="11360.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="us-gaap_DerivativeCollateralRightToReclaimSecurities" order="11440.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountOffsetAgainstCollateral" order="11520.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="us-gaap_DerivativeFairValueOfDerivativeAssetAmountNotOffsetAgainstCollateral" order="11630.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet" order="11670.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet" order="11710.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="sgu_DerivativeFairValueGrossAmountNotOffsetFinancialInstrumentsNet" order="11750.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="sgu_CashCollateralReceivedFromNotOffsetAgainstDerivativeAssetsAndLiabilities" order="11790.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_FairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsLineItems" xlink:to="us-gaap_DerivativeFairValueOfDerivativeNet" order="11830.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureDerivativesAndHedgingDisclosuresAndFairValueMeasurementsEffectOfDerivativeInstrumentsOnStatementOfOperationsDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureDerivativesAndHedgingDisclosuresAndFairValueMeasurementsEffectOfDerivativeInstrumentsOnStatementOfOperationsDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureDerivativesAndHedgingDisclosuresAndFairValueMeasurementsEffectOfDerivativeInstrumentsOnStatementOfOperationsDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnrealizedGainLossOnDerivatives" xlink:type="locator" xlink:label="us-gaap_UnrealizedGainLossOnDerivatives" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeGainLossOnDerivativeNet" xlink:type="locator" xlink:label="us-gaap_DerivativeGainLossOnDerivativeNet" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_OperatingCostsAndExpensesMember" xlink:type="locator" xlink:label="sgu_OperatingCostsAndExpensesMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CostOfServicesMember" xlink:type="locator" xlink:label="sgu_CostOfServicesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CostOfSalesMember" xlink:type="locator" xlink:label="us-gaap_CostOfSalesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommodityContractMember" xlink:type="locator" xlink:label="us-gaap_CommodityContractMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:type="locator" xlink:label="us-gaap_DerivativeContractTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:type="locator" xlink:label="us-gaap_DerivativeInstrumentRiskAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NondesignatedMember" xlink:type="locator" xlink:label="us-gaap_NondesignatedMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:type="locator" xlink:label="us-gaap_HedgingDesignationDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationAxis" xlink:type="locator" xlink:label="us-gaap_HedgingDesignationAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementsRecurringMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:type="locator" xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:type="locator" xlink:label="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems" xlink:type="locator" xlink:label="us-gaap_DerivativeInstrumentsGainLossLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DerivativeInstrumentsGainLossLineItems" xlink:to="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:to="us-gaap_FairValueByMeasurementFrequencyAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FairValueByMeasurementFrequencyAxis" xlink:to="us-gaap_FairValueMeasurementFrequencyDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueMeasurementFrequencyDomain" xlink:to="us-gaap_FairValueMeasurementsRecurringMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:to="us-gaap_HedgingDesignationAxis" order="10140.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_HedgingDesignationAxis" xlink:to="us-gaap_HedgingDesignationDomain" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_HedgingDesignationDomain" xlink:to="us-gaap_NondesignatedMember" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:to="us-gaap_DerivativeInstrumentRiskAxis" order="10240.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DerivativeInstrumentRiskAxis" xlink:to="us-gaap_DerivativeContractTypeDomain" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativeContractTypeDomain" xlink:to="us-gaap_CommodityContractMember" order="10290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:to="us-gaap_IncomeStatementLocationAxis" order="10340.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="us-gaap_IncomeStatementLocationDomain" order="10370.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementLocationDomain" xlink:to="us-gaap_CostOfSalesMember" order="10390.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementLocationDomain" xlink:to="sgu_CostOfServicesMember" order="10410.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementLocationDomain" xlink:to="sgu_OperatingCostsAndExpensesMember" order="10430.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativeInstrumentsGainLossLineItems" xlink:to="us-gaap_DerivativeGainLossOnDerivativeNet" order="10460.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DerivativeInstrumentsGainLossLineItems" xlink:to="us-gaap_UnrealizedGainLossOnDerivatives" order="10640.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureInventoriesAdditionalInformationDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureInventoriesAdditionalInformationDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureInventoriesAdditionalInformationDetail">
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MaximumPercentageOfProductPurchases" xlink:type="locator" xlink:label="sgu_MaximumPercentageOfProductPurchases" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_PercentageOfProductPurchases" xlink:type="locator" xlink:label="sgu_PercentageOfProductPurchases" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MarketBasedProductSupplyContractsInGallons" xlink:type="locator" xlink:label="sgu_MarketBasedProductSupplyContractsInGallons" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_HeatingOilAndOtherFuelInventories" xlink:type="locator" xlink:label="sgu_HeatingOilAndOtherFuelInventories" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_GlobalCompaniesLLCMember" xlink:type="locator" xlink:label="sgu_GlobalCompaniesLLCMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MotivaEnterprisesLLCMember" xlink:type="locator" xlink:label="sgu_MotivaEnterprisesLLCMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_ShellOilCompanyMember" xlink:type="locator" xlink:label="sgu_ShellOilCompanyMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:type="locator" xlink:label="us-gaap_RelatedPartyDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DieselAndGasolineMember" xlink:type="locator" xlink:label="sgu_DieselAndGasolineMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_HomeHeatingOilAndPropaneMember" xlink:type="locator" xlink:label="sgu_HomeHeatingOilAndPropaneMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_EnergyDomain" xlink:type="locator" xlink:label="srt_EnergyDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_EnergyDomain" xlink:type="locator" xlink:label="srt_EnergyDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_EnergyAxis" xlink:type="locator" xlink:label="srt_EnergyAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InventoryCurrentTable" xlink:type="locator" xlink:label="us-gaap_InventoryCurrentTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InventoryLineItems" xlink:type="locator" xlink:label="us-gaap_InventoryLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_InventoryLineItems" xlink:to="us-gaap_InventoryCurrentTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_InventoryCurrentTable" xlink:to="srt_EnergyAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_EnergyAxis" xlink:to="srt_EnergyDomain_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_EnergyAxis" xlink:to="srt_EnergyDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_EnergyDomain" xlink:to="sgu_HomeHeatingOilAndPropaneMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_EnergyDomain" xlink:to="sgu_DieselAndGasolineMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_InventoryCurrentTable" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" order="10120.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="sgu_ShellOilCompanyMember" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="sgu_MotivaEnterprisesLLCMember" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="sgu_GlobalCompaniesLLCMember" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_InventoryLineItems" xlink:to="sgu_HeatingOilAndOtherFuelInventories" order="10240.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_InventoryLineItems" xlink:to="sgu_MarketBasedProductSupplyContractsInGallons" order="10280.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_InventoryLineItems" xlink:to="sgu_PercentageOfProductPurchases" order="10390.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_InventoryLineItems" xlink:to="sgu_MaximumPercentageOfProductPurchases" order="10470.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosurePropertyAndEquipmentComponentOfPropertyAndEquipmentDetail" xlink:href="sgu-20200930.xsd#Role_DisclosurePropertyAndEquipmentComponentOfPropertyAndEquipmentDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosurePropertyAndEquipmentComponentOfPropertyAndEquipmentDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentNet" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:type="locator" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentGross" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:type="locator" xlink:label="us-gaap_FurnitureAndFixturesMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_TanksAndEquipmentMember" xlink:type="locator" xlink:label="sgu_TanksAndEquipmentMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_FleetAndOtherEquipmentMember" xlink:type="locator" xlink:label="sgu_FleetAndOtherEquipmentMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_BuildingAndLeaseholdImprovementsMember" xlink:type="locator" xlink:label="sgu_BuildingAndLeaseholdImprovementsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LandAndLandImprovementsMember" xlink:type="locator" xlink:label="us-gaap_LandAndLandImprovementsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_PropertyPlantAndEquipmentLineItems" xlink:to="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" order="10030.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="us-gaap_PropertyPlantAndEquipmentByTypeAxis" order="10060.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_LandAndLandImprovementsMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="sgu_BuildingAndLeaseholdImprovementsMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="sgu_FleetAndOtherEquipmentMember" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="sgu_TanksAndEquipmentMember" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_FurnitureAndFixturesMember" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentGross" order="10220.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentLineItems" xlink:to="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" order="10460.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentNet" order="10500.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureBusinessCombinationsAdditionalInformationDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureBusinessCombinationsAdditionalInformationDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureBusinessCombinationsAdditionalInformationDetail">
    <link:loc xlink:href="sgu-20200930.xsd#sgu_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetWorkingCapital" xlink:type="locator" xlink:label="sgu_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetWorkingCapital" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsIncludingGoodwill" xlink:type="locator" xlink:label="sgu_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsIncludingGoodwill" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireBusinessesGross" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationConsiderationTransferred1" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NumberOfBusinessesAcquired" xlink:type="locator" xlink:label="us-gaap_NumberOfBusinessesAcquired" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_HeatingOilDealerAndMotorFuelDealerMember" xlink:type="locator" xlink:label="sgu_HeatingOilDealerAndMotorFuelDealerMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MotorFuelDealerMember" xlink:type="locator" xlink:label="sgu_MotorFuelDealerMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_AcquiredBusinessMember" xlink:type="locator" xlink:label="sgu_AcquiredBusinessMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_LiquidProductDealersMember" xlink:type="locator" xlink:label="sgu_LiquidProductDealersMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_Fiscal2019AcquisitionMember" xlink:type="locator" xlink:label="sgu_Fiscal2019AcquisitionMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_HeatingOilDealersMember" xlink:type="locator" xlink:label="sgu_HeatingOilDealersMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_BusinessAcquisitionAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="sgu_HeatingOilDealersMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="sgu_Fiscal2019AcquisitionMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="sgu_LiquidProductDealersMember" order="10290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="sgu_AcquiredBusinessMember" order="10310.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="sgu_MotorFuelDealerMember" order="10390.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="sgu_HeatingOilDealerAndMotorFuelDealerMember" order="10410.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_NumberOfBusinessesAcquired" order="10540.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationConsiderationTransferred1" order="10580.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_PaymentsToAcquireBusinessesGross" order="10660.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred" order="10700.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="sgu_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsIncludingGoodwill" order="10740.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" order="10780.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="sgu_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetWorkingCapital" order="10820.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureBusinessCombinationsSummaryOfFinalFairValuesAndPurchasePriceAllocationsInAggregateOfAssetsAcquiredAndLiabilitiesAssumedDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureBusinessCombinationsSummaryOfFinalFairValuesAndPurchasePriceAllocationsInAggregateOfAssetsAcquiredAndLiabilitiesAssumedDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureBusinessCombinationsSummaryOfFinalFairValuesAndPurchasePriceAllocationsInAggregateOfAssetsAcquiredAndLiabilitiesAssumedDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Goodwill" xlink:type="locator" xlink:label="us-gaap_Goodwill" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationConsiderationTransferred1" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCustomerCreditBalances" xlink:type="locator" xlink:label="sgu_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCustomerCreditBalances" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenue" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenue" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccruedExpensesAndOtherCurrentLiabilities" xlink:type="locator" xlink:label="sgu_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccruedExpensesAndOtherCurrentLiabilities" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_AcquiredBusinessMember" xlink:type="locator" xlink:label="sgu_AcquiredBusinessMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" order="10100.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_BusinessAcquisitionAxis" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain" order="10160.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="sgu_AcquiredBusinessMember" order="10180.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory" order="10230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets" order="10250.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill" order="10290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="sgu_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccruedExpensesAndOtherCurrentLiabilities" order="10310.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenue" order="10330.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="sgu_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCustomerCreditBalances" order="10350.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" order="10370.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" order="10390.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationConsiderationTransferred1" order="10410.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_Goodwill" order="10450.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureIntangibleAssetsSubjectToAmortizationDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureIntangibleAssetsSubjectToAmortizationDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureIntangibleAssetsSubjectToAmortizationDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_TradeNamesAndOtherIntangiblesMember" xlink:type="locator" xlink:label="sgu_TradeNamesAndOtherIntangiblesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CustomerListsMember" xlink:type="locator" xlink:label="us-gaap_CustomerListsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" order="10030.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:to="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" order="10060.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="us-gaap_CustomerListsMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="sgu_TradeNamesAndOtherIntangiblesMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_FiniteLivedIntangibleAssetsGross" order="10160.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" order="10320.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_FiniteLivedIntangibleAssetsNet" order="10480.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureLongTermDebtAndBankFacilityBorrowingsCompanySDebtDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureLongTermDebtAndBankFacilityBorrowingsCompanySDebtDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureLongTermDebtAndBankFacilityBorrowingsCompanySDebtDetail">
    <link:loc xlink:href="sgu-20200930.xsd#sgu_LongTermDebtNoncurrentFairValue" xlink:type="locator" xlink:label="sgu_LongTermDebtNoncurrentFairValue" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_LongtermDebtFairValueCurrent" xlink:type="locator" xlink:label="sgu_LongtermDebtFairValueCurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtFairValue" xlink:type="locator" xlink:label="us-gaap_LongTermDebtFairValue" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_LinesOfCreditCurrentFairValue" xlink:type="locator" xlink:label="sgu_LinesOfCreditCurrentFairValue" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:type="locator" xlink:label="us-gaap_LongTermDebtNoncurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LoansPayableToBankCurrent" xlink:type="locator" xlink:label="us-gaap_LoansPayableToBankCurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebt" xlink:type="locator" xlink:label="us-gaap_LongTermDebt" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_LinesOfCreditCurrentCarryingValue" xlink:type="locator" xlink:label="sgu_LinesOfCreditCurrentCarryingValue" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_TermLoanMember" xlink:type="locator" xlink:label="sgu_TermLoanMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:type="locator" xlink:label="us-gaap_RevolvingCreditFacilityMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:type="locator" xlink:label="us-gaap_CreditFacilityDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:type="locator" xlink:label="us-gaap_CreditFacilityAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_CreditFacilityAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_CreditFacilityAxis" xlink:to="us-gaap_CreditFacilityDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="us-gaap_RevolvingCreditFacilityMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="sgu_TermLoanMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="sgu_LinesOfCreditCurrentCarryingValue" order="10220.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LongTermDebt" order="10260.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LoansPayableToBankCurrent" order="10340.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LongTermDebtNoncurrent" order="10380.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="sgu_LinesOfCreditCurrentFairValue" order="10450.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LongTermDebtFairValue" order="10490.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="sgu_LongtermDebtFairValueCurrent" order="10570.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="sgu_LongTermDebtNoncurrentFairValue" order="10610.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureLongTermDebtAndBankFacilityBorrowingsCompanySDebtParentheticalDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureLongTermDebtAndBankFacilityBorrowingsCompanySDebtParentheticalDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureLongTermDebtAndBankFacilityBorrowingsCompanySDebtParentheticalDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCredit" xlink:type="locator" xlink:label="us-gaap_LineOfCredit" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTerm" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentTerm" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredFinanceCostsNet" xlink:type="locator" xlink:label="us-gaap_DeferredFinanceCostsNet" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:type="locator" xlink:label="us-gaap_RevolvingCreditFacilityMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_FifthAmendmentMember" xlink:type="locator" xlink:label="sgu_FifthAmendmentMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityLenderDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityAxis" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_TermLoanMember" xlink:type="locator" xlink:label="sgu_TermLoanMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:type="locator" xlink:label="us-gaap_CreditFacilityDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:type="locator" xlink:label="us-gaap_CreditFacilityAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_CreditFacilityAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_CreditFacilityAxis" xlink:to="us-gaap_CreditFacilityDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="sgu_TermLoanMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_LineOfCreditFacilityAxis" order="10100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_LineOfCreditFacilityAxis" xlink:to="us-gaap_LineOfCreditFacilityLenderDomain" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLenderDomain" xlink:to="sgu_FifthAmendmentMember" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="us-gaap_RevolvingCreditFacilityMember" order="10250.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DeferredFinanceCostsNet" order="10280.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentTerm" order="10350.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LineOfCredit" order="10370.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureLongTermDebtAndBankFacilityBorrowingsAdditionalInformationDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureLongTermDebtAndBankFacilityBorrowingsAdditionalInformationDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureLongTermDebtAndBankFacilityBorrowingsAdditionalInformationDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AmountOfRestrictedNetAssetsForConsolidatedAndUnconsolidatedSubsidiaries" xlink:type="locator" xlink:label="us-gaap_AmountOfRestrictedNetAssetsForConsolidatedAndUnconsolidatedSubsidiaries" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_AvailabilityUnderCreditAgreement" xlink:type="locator" xlink:label="sgu_AvailabilityUnderCreditAgreement" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LinesOfCreditCurrent" xlink:type="locator" xlink:label="us-gaap_LinesOfCreditCurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtFairValue" xlink:type="locator" xlink:label="us-gaap_LongTermDebtFairValue" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount" xlink:type="locator" xlink:label="us-gaap_LettersOfCreditOutstandingAmount" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeAmountOfHedgedItem" xlink:type="locator" xlink:label="us-gaap_DerivativeAmountOfHedgedItem" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DebtInstrumentLeverageRatioPeriodTwo" xlink:type="locator" xlink:label="sgu_DebtInstrumentLeverageRatioPeriodTwo" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DebtInstrumentLeverageRatioPeriodOne" xlink:type="locator" xlink:label="sgu_DebtInstrumentLeverageRatioPeriodOne" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_AvailabilityPercentageToMaximumFacilitySize" xlink:type="locator" xlink:label="sgu_AvailabilityPercentageToMaximumFacilitySize" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MinimumFixedChargeCoverageRatioOnRevolvingCreditFacilities" xlink:type="locator" xlink:label="sgu_MinimumFixedChargeCoverageRatioOnRevolvingCreditFacilities" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentagePeriodTwo" xlink:type="locator" xlink:label="sgu_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentagePeriodTwo" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentagePeriodOne" xlink:type="locator" xlink:label="sgu_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentagePeriodOne" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentInterestRateEffectivePercentage" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_AdditionalAnnualPaymentToTermLoanFacilityPercentageOfExcessCashFlow" xlink:type="locator" xlink:label="sgu_AdditionalAnnualPaymentToTermLoanFacilityPercentageOfExcessCashFlow" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentPeriodicPaymentPrincipal" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentPeriodicPaymentPrincipal" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MaximumIncreaseAllowedWithoutBankConsulting" xlink:type="locator" xlink:label="sgu_MaximumIncreaseAllowedWithoutBankConsulting" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTerm" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentTerm" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityExpirationDate1" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityExpirationDate1" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_LineOfCreditFacilityAdditionalBorrowingCapacityForWorkingCapitalNeeds" xlink:type="locator" xlink:label="sgu_LineOfCreditFacilityAdditionalBorrowingCapacityForWorkingCapitalNeeds" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentFaceAmount" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_LineOfCreditFacilityMaximumBorrowingCapacityDuringHeatingSeason" xlink:type="locator" xlink:label="sgu_LineOfCreditFacilityMaximumBorrowingCapacityDuringHeatingSeason" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:type="locator" xlink:label="us-gaap_RevolvingCreditFacilityMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:type="locator" xlink:label="srt_MinimumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:type="locator" xlink:label="srt_MaximumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:type="locator" xlink:label="srt_RangeMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:type="locator" xlink:label="srt_RangeAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_AnnuallyMember" xlink:type="locator" xlink:label="sgu_AnnuallyMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_QuarterlyMember" xlink:type="locator" xlink:label="sgu_QuarterlyMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentRedemptionPeriodDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentRedemptionPeriodDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodAxis" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentRedemptionPeriodAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CreditAgreementMember" xlink:type="locator" xlink:label="sgu_CreditAgreementMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityLenderDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityAxis" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_TermLoanMember" xlink:type="locator" xlink:label="sgu_TermLoanMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:type="locator" xlink:label="us-gaap_CreditFacilityDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:type="locator" xlink:label="us-gaap_CreditFacilityAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_CreditFacilityAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_CreditFacilityAxis" xlink:to="us-gaap_CreditFacilityDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="sgu_TermLoanMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_LineOfCreditFacilityAxis" order="10120.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_LineOfCreditFacilityAxis" xlink:to="us-gaap_LineOfCreditFacilityLenderDomain" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LineOfCreditFacilityLenderDomain" xlink:to="sgu_CreditAgreementMember" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_DebtInstrumentRedemptionPeriodAxis" order="10440.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_DebtInstrumentRedemptionPeriodAxis" xlink:to="us-gaap_DebtInstrumentRedemptionPeriodDomain_2" order="10450.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DebtInstrumentRedemptionPeriodAxis" xlink:to="us-gaap_DebtInstrumentRedemptionPeriodDomain" order="10470.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentRedemptionPeriodDomain" xlink:to="sgu_QuarterlyMember" order="10490.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentRedemptionPeriodDomain" xlink:to="sgu_AnnuallyMember" order="10510.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="srt_RangeAxis" order="10520.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="10550.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MaximumMember" order="10570.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MinimumMember" order="10590.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="us-gaap_RevolvingCreditFacilityMember" order="10670.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" order="11020.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="sgu_LineOfCreditFacilityMaximumBorrowingCapacityDuringHeatingSeason" order="11060.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentFaceAmount" order="11100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="sgu_LineOfCreditFacilityAdditionalBorrowingCapacityForWorkingCapitalNeeds" order="11140.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LineOfCreditFacilityExpirationDate1" order="11180.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentTerm" order="11220.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="sgu_MaximumIncreaseAllowedWithoutBankConsulting" order="11290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentPeriodicPaymentPrincipal" order="11360.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="sgu_AdditionalAnnualPaymentToTermLoanFacilityPercentageOfExcessCashFlow" order="11380.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentInterestRateEffectivePercentage" order="11450.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="sgu_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentagePeriodOne" order="11560.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="sgu_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentagePeriodTwo" order="11580.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="sgu_MinimumFixedChargeCoverageRatioOnRevolvingCreditFacilities" order="11630.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="sgu_AvailabilityPercentageToMaximumFacilitySize" order="11650.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="sgu_DebtInstrumentLeverageRatioPeriodOne" order="11670.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="sgu_DebtInstrumentLeverageRatioPeriodTwo" order="11690.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DerivativeAmountOfHedgedItem" order="11740.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LettersOfCreditOutstandingAmount" order="11780.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LongTermDebtFairValue" order="11820.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LinesOfCreditCurrent" order="11860.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="sgu_AvailabilityUnderCreditAgreement" order="11930.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_AmountOfRestrictedNetAssetsForConsolidatedAndUnconsolidatedSubsidiaries" order="11970.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureEmployeeBenefitPlansAdditionalInformationDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureEmployeeBenefitPlansAdditionalInformationDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureEmployeeBenefitPlansAdditionalInformationDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DiscountRateToDeterminePeriodicPensionExpense" xlink:type="locator" xlink:label="sgu_DiscountRateToDeterminePeriodicPensionExpense" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_RatePensionPlanAssetsExpectToEarn" xlink:type="locator" xlink:label="sgu_RatePensionPlanAssetsExpectToEarn" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedAmortizationNextFiscalYear" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanExpectedAmortizationNextFiscalYear" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_NetActuarialLossBalanceInAccumulatedOtherComprehensiveIncomeToBeAmortized" xlink:type="locator" xlink:label="sgu_NetActuarialLossBalanceInAccumulatedOtherComprehensiveIncomeToBeAmortized" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_NumberOfDefinedBenefitPensionPlans" xlink:type="locator" xlink:label="sgu_NumberOfDefinedBenefitPensionPlans" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MultiemployerPlansWithdrawalObligation" xlink:type="locator" xlink:label="us-gaap_MultiemployerPlansWithdrawalObligation" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:type="locator" xlink:label="us-gaap_OtherLiabilitiesNoncurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:type="locator" xlink:label="us-gaap_AccruedLiabilitiesCurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedContributionPlanNumberOfEmployees" xlink:type="locator" xlink:label="us-gaap_DefinedContributionPlanNumberOfEmployees" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MultiemployerPlansWithdrawalObligationAnnualInstallmentPayment" xlink:type="locator" xlink:label="sgu_MultiemployerPlansWithdrawalObligationAnnualInstallmentPayment" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_EmployeeBenefitPaymentsPeriod" xlink:type="locator" xlink:label="sgu_EmployeeBenefitPaymentsPeriod" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MultiemployerPlansWithdrawalUndiscountedObligation" xlink:type="locator" xlink:label="sgu_MultiemployerPlansWithdrawalUndiscountedObligation" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DefinedBenefitPlanContributionOfPensionFundInExcessOfTotalContribution" xlink:type="locator" xlink:label="sgu_DefinedBenefitPlanContributionOfPensionFundInExcessOfTotalContribution" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_GreenZoneMultiemployerPlansFundedPercentage" xlink:type="locator" xlink:label="sgu_GreenZoneMultiemployerPlansFundedPercentage" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_YellowZoneMultiemployerPlansFundedPercentage" xlink:type="locator" xlink:label="sgu_YellowZoneMultiemployerPlansFundedPercentage" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_RedZoneMultiemployerPlansFundedPercentage" xlink:type="locator" xlink:label="sgu_RedZoneMultiemployerPlansFundedPercentage" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MultiemployerPlanPensionSignificantEmployeesCoveredByCollectiveBargainingArrangementToAllParticipantsPercentage" xlink:type="locator" xlink:label="us-gaap_MultiemployerPlanPensionSignificantEmployeesCoveredByCollectiveBargainingArrangementToAllParticipantsPercentage" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualDistributionPaid" xlink:type="locator" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualDistributionPaid" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DeferredCompensationPlanVestingPercentage" xlink:type="locator" xlink:label="sgu_DeferredCompensationPlanVestingPercentage" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_GainsInterestCashProceedsPercentageFromSaleOfGeneralPartnerUnits" xlink:type="locator" xlink:label="sgu_GainsInterestCashProceedsPercentageFromSaleOfGeneralPartnerUnits" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DeferredCompensationArrangementWithIndividualCashDistributionPerUnit" xlink:type="locator" xlink:label="sgu_DeferredCompensationArrangementWithIndividualCashDistributionPerUnit" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_IncentiveDistributionPercentageOfAvailableCashInExcessOfMinimumQuarterlyDistribution" xlink:type="locator" xlink:label="sgu_IncentiveDistributionPercentageOfAvailableCashInExcessOfMinimumQuarterlyDistribution" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount" xlink:type="locator" xlink:label="us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DefinedContributionPlanEmployeeContributionPercentage" xlink:type="locator" xlink:label="sgu_DefinedContributionPlanEmployeeContributionPercentage" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent" xlink:type="locator" xlink:label="us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanCashAndCashEquivalentsMember" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanCashAndCashEquivalentsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanAssetCategoriesDomain" xlink:type="locator" xlink:label="us-gaap_PlanAssetCategoriesDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanAssetCategoriesDomain" xlink:type="locator" xlink:label="us-gaap_PlanAssetCategoriesDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_InternationalEquityMember" xlink:type="locator" xlink:label="sgu_InternationalEquityMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DomesticEquitiesMember" xlink:type="locator" xlink:label="sgu_DomesticEquitiesMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DomesticFixedIncomeSecurityMember" xlink:type="locator" xlink:label="sgu_DomesticFixedIncomeSecurityMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioForecastMember" xlink:type="locator" xlink:label="srt_ScenarioForecastMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="srt_ScenarioUnspecifiedDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementScenarioAxis" xlink:type="locator" xlink:label="srt_StatementScenarioAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_FrozenDefinedBenefitPensionPlansMember" xlink:type="locator" xlink:label="sgu_FrozenDefinedBenefitPensionPlansMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:type="locator" xlink:label="us-gaap_FairValueInputsLevel2Member" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:type="locator" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MultiemployerPensionPlansMember" xlink:type="locator" xlink:label="sgu_MultiemployerPensionPlansMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetirementPlanNameDomain" xlink:type="locator" xlink:label="us-gaap_RetirementPlanNameDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetirementPlanNameDomain" xlink:type="locator" xlink:label="us-gaap_RetirementPlanNameDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetirementPlanNameAxis" xlink:type="locator" xlink:label="us-gaap_RetirementPlanNameAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember" xlink:type="locator" xlink:label="us-gaap_PensionPlansDefinedBenefitMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_ContractRenewalMember" xlink:type="locator" xlink:label="sgu_ContractRenewalMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CollectiveBargainingArrangementDomain" xlink:type="locator" xlink:label="us-gaap_CollectiveBargainingArrangementDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CollectiveBargainingArrangementDomain" xlink:type="locator" xlink:label="us-gaap_CollectiveBargainingArrangementDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CollectiveBargainingArrangementAxis" xlink:type="locator" xlink:label="us-gaap_CollectiveBargainingArrangementAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ExecutiveOfficerMember" xlink:type="locator" xlink:label="srt_ExecutiveOfficerMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_ManagementIncentiveCompensationPlanMember" xlink:type="locator" xlink:label="sgu_ManagementIncentiveCompensationPlanMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_ManagementAndGeneralPartnerMember" xlink:type="locator" xlink:label="sgu_ManagementAndGeneralPartnerMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ChiefExecutiveOfficerMember" xlink:type="locator" xlink:label="srt_ChiefExecutiveOfficerMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_NonEmployeesMember" xlink:type="locator" xlink:label="sgu_NonEmployeesMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_EmployeesAndConsultantsMember" xlink:type="locator" xlink:label="sgu_EmployeesAndConsultantsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ManagementMember" xlink:type="locator" xlink:label="srt_ManagementMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:type="locator" xlink:label="srt_TitleOfIndividualWithRelationshipToEntityDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:type="locator" xlink:label="srt_TitleOfIndividualWithRelationshipToEntityDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualAxis" xlink:type="locator" xlink:label="srt_TitleOfIndividualAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:type="locator" xlink:label="srt_MaximumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:type="locator" xlink:label="srt_MinimumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:type="locator" xlink:label="srt_RangeMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:type="locator" xlink:label="srt_RangeAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" xlink:type="locator" xlink:label="us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:type="locator" xlink:label="us-gaap_RetirementPlanTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:type="locator" xlink:label="us-gaap_RetirementPlanTypeDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetirementPlanTypeAxis" xlink:type="locator" xlink:label="us-gaap_RetirementPlanTypeAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_RetirementPlanTypeAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_RetirementPlanTypeAxis" xlink:to="us-gaap_RetirementPlanTypeDomain_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RetirementPlanTypeAxis" xlink:to="us-gaap_RetirementPlanTypeDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RetirementPlanTypeDomain" xlink:to="us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="srt_RangeAxis" order="10100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MinimumMember" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MaximumMember" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="srt_TitleOfIndividualAxis" order="10180.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_TitleOfIndividualAxis" xlink:to="srt_TitleOfIndividualWithRelationshipToEntityDomain_2" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_TitleOfIndividualAxis" xlink:to="srt_TitleOfIndividualWithRelationshipToEntityDomain" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="srt_ManagementMember" order="10230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="sgu_EmployeesAndConsultantsMember" order="10450.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="sgu_NonEmployeesMember" order="10470.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="srt_ChiefExecutiveOfficerMember" order="10490.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="sgu_ManagementAndGeneralPartnerMember" order="10550.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="sgu_ManagementIncentiveCompensationPlanMember" order="10570.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="srt_ExecutiveOfficerMember" order="10590.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_CollectiveBargainingArrangementAxis" order="10600.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_CollectiveBargainingArrangementAxis" xlink:to="us-gaap_CollectiveBargainingArrangementDomain_2" order="10610.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_CollectiveBargainingArrangementAxis" xlink:to="us-gaap_CollectiveBargainingArrangementDomain" order="10630.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CollectiveBargainingArrangementDomain" xlink:to="sgu_ContractRenewalMember" order="10650.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RetirementPlanTypeDomain" xlink:to="us-gaap_PensionPlansDefinedBenefitMember" order="10710.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_RetirementPlanNameAxis" order="10720.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_RetirementPlanNameAxis" xlink:to="us-gaap_RetirementPlanNameDomain_2" order="10730.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RetirementPlanNameAxis" xlink:to="us-gaap_RetirementPlanNameDomain" order="10750.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RetirementPlanNameDomain" xlink:to="sgu_MultiemployerPensionPlansMember" order="10770.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_FairValueByFairValueHierarchyLevelAxis" order="11000.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" order="11030.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="us-gaap_FairValueInputsLevel2Member" order="11050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RetirementPlanTypeDomain" xlink:to="sgu_FrozenDefinedBenefitPensionPlansMember" order="11190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="srt_StatementScenarioAxis" order="11200.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_StatementScenarioAxis" xlink:to="srt_ScenarioUnspecifiedDomain" order="11230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ScenarioUnspecifiedDomain" xlink:to="srt_ScenarioForecastMember" order="11250.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RetirementPlanTypeDomain" xlink:to="sgu_DomesticFixedIncomeSecurityMember" order="11310.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RetirementPlanTypeDomain" xlink:to="sgu_DomesticEquitiesMember" order="11330.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RetirementPlanTypeDomain" xlink:to="sgu_InternationalEquityMember" order="11350.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" order="11360.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:to="us-gaap_PlanAssetCategoriesDomain_2" order="11370.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:to="us-gaap_PlanAssetCategoriesDomain" order="11390.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PlanAssetCategoriesDomain" xlink:to="us-gaap_DefinedBenefitPlanCashAndCashEquivalentsMember" order="11410.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent" order="11440.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="sgu_DefinedContributionPlanEmployeeContributionPercentage" order="11500.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount" order="11560.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="sgu_IncentiveDistributionPercentageOfAvailableCashInExcessOfMinimumQuarterlyDistribution" order="11710.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="sgu_DeferredCompensationArrangementWithIndividualCashDistributionPerUnit" order="11730.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="sgu_GainsInterestCashProceedsPercentageFromSaleOfGeneralPartnerUnits" order="11780.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="sgu_DeferredCompensationPlanVestingPercentage" order="11830.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_DeferredCompensationArrangementWithIndividualDistributionPaid" order="11920.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_MultiemployerPlanPensionSignificantEmployeesCoveredByCollectiveBargainingArrangementToAllParticipantsPercentage" order="12130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="sgu_RedZoneMultiemployerPlansFundedPercentage" order="12200.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="sgu_YellowZoneMultiemployerPlansFundedPercentage" order="12220.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="sgu_GreenZoneMultiemployerPlansFundedPercentage" order="12240.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="sgu_DefinedBenefitPlanContributionOfPensionFundInExcessOfTotalContribution" order="12310.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="sgu_MultiemployerPlansWithdrawalUndiscountedObligation" order="12400.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="sgu_EmployeeBenefitPaymentsPeriod" order="12420.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="sgu_MultiemployerPlansWithdrawalObligationAnnualInstallmentPayment" order="12440.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_DefinedContributionPlanNumberOfEmployees" order="12490.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_AccruedLiabilitiesCurrent" order="12510.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_OtherLiabilitiesNoncurrent" order="12530.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_MultiemployerPlansWithdrawalObligation" order="12550.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="sgu_NumberOfDefinedBenefitPensionPlans" order="12600.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent" order="12650.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="sgu_NetActuarialLossBalanceInAccumulatedOtherComprehensiveIncomeToBeAmortized" order="12720.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_DefinedBenefitPlanExpectedAmortizationNextFiscalYear" order="12740.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="sgu_RatePensionPlanAssetsExpectToEarn" order="12790.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="sgu_DiscountRateToDeterminePeriodicPensionExpense" order="12840.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage" order="12930.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear" order="13040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths" order="13090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" order="13110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" order="13130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" order="13150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" order="13170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter" order="13190.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureParticipationAndContributionsToMultiEmployerPensionPlansDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureParticipationAndContributionsToMultiEmployerPensionPlansDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureParticipationAndContributionsToMultiEmployerPensionPlansDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MultiemployerPlanPensionSignificantCollectiveBargainingArrangementExpirationDate" xlink:type="locator" xlink:label="us-gaap_MultiemployerPlanPensionSignificantCollectiveBargainingArrangementExpirationDate" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MultiemployerPlanPensionSignificantSurchargeFixedList" xlink:type="locator" xlink:label="us-gaap_MultiemployerPlanPensionSignificantSurchargeFixedList" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MultiemployerPlanPensionSignificantEmployerContributionCost" xlink:type="locator" xlink:label="us-gaap_MultiemployerPlanPensionSignificantEmployerContributionCost" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MultiemployerPlanPensionSignificantFundingImprovementOrRehabilitationPlanImplementationStatusFixedList" xlink:type="locator" xlink:label="us-gaap_MultiemployerPlanPensionSignificantFundingImprovementOrRehabilitationPlanImplementationStatusFixedList" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MultiemployerPlanPensionSignificantCertifiedZoneStatusFixedList" xlink:type="locator" xlink:label="us-gaap_MultiemployerPlanPensionSignificantCertifiedZoneStatusFixedList" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MultiemployerPlanPensionSignificantPlanNumber" xlink:type="locator" xlink:label="us-gaap_MultiemployerPlanPensionSignificantPlanNumber" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_EmployerIdentificationNumberOrPensionPlanNumber" xlink:type="locator" xlink:label="sgu_EmployerIdentificationNumberOrPensionPlanNumber" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:type="locator" xlink:label="srt_MaximumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:type="locator" xlink:label="srt_MinimumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:type="locator" xlink:label="srt_RangeMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:type="locator" xlink:label="srt_RangeAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember" xlink:type="locator" xlink:label="us-gaap_PensionPlansDefinedBenefitMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:type="locator" xlink:label="us-gaap_RetirementPlanTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetirementPlanTypeAxis" xlink:type="locator" xlink:label="us-gaap_RetirementPlanTypeAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_LocalFourHundredAndFortyFivePensionFundMember" xlink:type="locator" xlink:label="sgu_LocalFourHundredAndFortyFivePensionFundMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_TeamstersLocalFourHundredAndSixtyNinePensionPlanMember" xlink:type="locator" xlink:label="sgu_TeamstersLocalFourHundredAndSixtyNinePensionPlanMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_AllOtherMultiemployerPensionPlansMember" xlink:type="locator" xlink:label="sgu_AllOtherMultiemployerPensionPlansMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_IAMNationalPensionFundMember" xlink:type="locator" xlink:label="sgu_IAMNationalPensionFundMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_LocalFourHundredAndSixtyThreePensionFundMember" xlink:type="locator" xlink:label="sgu_LocalFourHundredAndSixtyThreePensionFundMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_LocalFiveHundredAndFiftyThreePensionFundMember" xlink:type="locator" xlink:label="sgu_LocalFiveHundredAndFiftyThreePensionFundMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_WestchesterTeamstersPensionFundMember" xlink:type="locator" xlink:label="sgu_WestchesterTeamstersPensionFundMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetirementPlanNameDomain" xlink:type="locator" xlink:label="us-gaap_RetirementPlanNameDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetirementPlanNameAxis" xlink:type="locator" xlink:label="us-gaap_RetirementPlanNameAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfMultiemployerPlansTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfMultiemployerPlansTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MultiemployerPlansLineItems" xlink:type="locator" xlink:label="us-gaap_MultiemployerPlansLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_MultiemployerPlansLineItems" xlink:to="us-gaap_ScheduleOfMultiemployerPlansTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfMultiemployerPlansTable" xlink:to="us-gaap_RetirementPlanNameAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RetirementPlanNameAxis" xlink:to="us-gaap_RetirementPlanNameDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RetirementPlanNameDomain" xlink:to="sgu_WestchesterTeamstersPensionFundMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RetirementPlanNameDomain" xlink:to="sgu_LocalFiveHundredAndFiftyThreePensionFundMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RetirementPlanNameDomain" xlink:to="sgu_LocalFourHundredAndSixtyThreePensionFundMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RetirementPlanNameDomain" xlink:to="sgu_IAMNationalPensionFundMember" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RetirementPlanNameDomain" xlink:to="sgu_AllOtherMultiemployerPensionPlansMember" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RetirementPlanNameDomain" xlink:to="sgu_TeamstersLocalFourHundredAndSixtyNinePensionPlanMember" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RetirementPlanNameDomain" xlink:to="sgu_LocalFourHundredAndFortyFivePensionFundMember" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfMultiemployerPlansTable" xlink:to="us-gaap_RetirementPlanTypeAxis" order="10220.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RetirementPlanTypeAxis" xlink:to="us-gaap_RetirementPlanTypeDomain" order="10250.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RetirementPlanTypeDomain" xlink:to="us-gaap_PensionPlansDefinedBenefitMember" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfMultiemployerPlansTable" xlink:to="srt_RangeAxis" order="10280.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="10310.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MinimumMember" order="10330.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MaximumMember" order="10350.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_MultiemployerPlansLineItems" xlink:to="sgu_EmployerIdentificationNumberOrPensionPlanNumber" order="10380.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_MultiemployerPlansLineItems" xlink:to="us-gaap_MultiemployerPlanPensionSignificantPlanNumber" order="10600.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_MultiemployerPlansLineItems" xlink:to="us-gaap_MultiemployerPlanPensionSignificantCertifiedZoneStatusFixedList" order="10820.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_MultiemployerPlansLineItems" xlink:to="us-gaap_MultiemployerPlanPensionSignificantFundingImprovementOrRehabilitationPlanImplementationStatusFixedList" order="11260.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_MultiemployerPlansLineItems" xlink:to="us-gaap_MultiemployerPlanPensionSignificantEmployerContributionCost" order="11480.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_MultiemployerPlansLineItems" xlink:to="us-gaap_MultiemployerPlanPensionSignificantSurchargeFixedList" order="12140.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_MultiemployerPlansLineItems" xlink:to="us-gaap_MultiemployerPlanPensionSignificantCollectiveBargainingArrangementExpirationDate" order="12360.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureNetPeriodicBenefitCostForPeriodReconciliationOfChangesInPlanAssetsProjectedBenefitObligationsAndAmountsRecognizedInOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureNetPeriodicBenefitCostForPeriodReconciliationOfChangesInPlanAssetsProjectedBenefitObligationsAndAmountsRecognizedInOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureNetPeriodicBenefitCostForPeriodReconciliationOfChangesInPlanAssetsProjectedBenefitObligationsAndAmountsRecognizedInOtherComprehensiveIncomeAndAccumulatedOtherComprehensiveIncomeDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax" xlink:type="locator" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossAfterTaxAbstract" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossAfterTaxAbstract" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DefinedBenefitDifferenceBetweenActualAndExpectedReturnOnPlanAssets" xlink:type="locator" xlink:label="sgu_DefinedBenefitDifferenceBetweenActualAndExpectedReturnOnPlanAssets" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTaxAbstract" xlink:type="locator" xlink:label="us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTaxAbstract" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanFundedStatusOfPlan" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanFundedStatusOfPlan" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanBenefitObligationPeriodIncreaseDecrease" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanBenefitObligationPeriodIncreaseDecrease" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanActuarialGainLoss" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanActuarialGainLoss" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DefinedBenefitPlanAnticipatedExpenses" xlink:type="locator" xlink:label="sgu_DefinedBenefitPlanAnticipatedExpenses" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DefinedBenefitPlanInvestmentAndOtherExpenses" xlink:type="locator" xlink:label="sgu_DefinedBenefitPlanInvestmentAndOtherExpenses" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DefinedBenefitPlanBenefitsPaidReducedFromProjectedBenefitObligation" xlink:type="locator" xlink:label="sgu_DefinedBenefitPlanBenefitsPaidReducedFromProjectedBenefitObligation" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DefinedBenefitPlanInterestCostIncludedInProjectedBenefitObligation" xlink:type="locator" xlink:label="sgu_DefinedBenefitPlanInterestCostIncludedInProjectedBenefitObligation" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanBenefitObligation" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanBenefitObligation" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsPeriodIncreaseDecrease" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsPeriodIncreaseDecrease" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanContributionsByEmployer" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PensionAndOtherPostretirementBenefitContributions" xlink:type="locator" xlink:label="us-gaap_PensionAndOtherPostretirementBenefitContributions" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DefinedBenefitPlanEmployerContributionAbstract" xlink:type="locator" xlink:label="sgu_DefinedBenefitPlanEmployerContributionAbstract" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DefinedBenefitPlanAmortizationOfUnrecognizedNetActuarialLoss" xlink:type="locator" xlink:label="sgu_DefinedBenefitPlanAmortizationOfUnrecognizedNetActuarialLoss" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DefinedBenefitPlanAnticipatedExpensesChargesAsNetPeriodicPensionCost" xlink:type="locator" xlink:label="sgu_DefinedBenefitPlanAnticipatedExpensesChargesAsNetPeriodicPensionCost" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DefinedBenefitDifferenceBetweenActualAndExpectedReturnOnPlanAssetsChargesAsNetPeriodicPensionCost" xlink:type="locator" xlink:label="sgu_DefinedBenefitDifferenceBetweenActualAndExpectedReturnOnPlanAssetsChargesAsNetPeriodicPensionCost" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DefinedBenefitPlanInvestmentAndOtherExpensesExcludedFromNetPeriodicPensionCost" xlink:type="locator" xlink:label="sgu_DefinedBenefitPlanInvestmentAndOtherExpensesExcludedFromNetPeriodicPensionCost" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DefinedBenefitPlanActualReturnOnPlanAssetsExcludedFromNetPeriodicPensionCost" xlink:type="locator" xlink:label="sgu_DefinedBenefitPlanActualReturnOnPlanAssetsExcludedFromNetPeriodicPensionCost" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanInterestCost" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanInterestCost" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_FrozenDefinedBenefitPensionPlansMember" xlink:type="locator" xlink:label="sgu_FrozenDefinedBenefitPensionPlansMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:type="locator" xlink:label="us-gaap_RetirementPlanTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetirementPlanTypeAxis" xlink:type="locator" xlink:label="us-gaap_RetirementPlanTypeAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" order="10180.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" xlink:to="us-gaap_RetirementPlanTypeAxis" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RetirementPlanTypeAxis" xlink:to="us-gaap_RetirementPlanTypeDomain" order="10240.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RetirementPlanTypeDomain" xlink:to="sgu_FrozenDefinedBenefitPensionPlansMember" order="10260.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract" order="10590.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_DefinedBenefitPlanInterestCost" order="10870.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="sgu_DefinedBenefitPlanActualReturnOnPlanAssetsExcludedFromNetPeriodicPensionCost" order="11010.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="sgu_DefinedBenefitPlanInvestmentAndOtherExpensesExcludedFromNetPeriodicPensionCost" order="11150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="sgu_DefinedBenefitDifferenceBetweenActualAndExpectedReturnOnPlanAssetsChargesAsNetPeriodicPensionCost" order="11290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="sgu_DefinedBenefitPlanAnticipatedExpensesChargesAsNetPeriodicPensionCost" order="11430.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="sgu_DefinedBenefitPlanAmortizationOfUnrecognizedNetActuarialLoss" order="11570.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" order="11710.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="sgu_DefinedBenefitPlanEmployerContributionAbstract" order="13840.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_PensionAndOtherPostretirementBenefitContributions" order="14120.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" order="14990.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" order="15270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets" order="15410.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_DefinedBenefitPlanContributionsByEmployer" order="15550.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid" order="15690.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsPeriodIncreaseDecrease" order="15830.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward" order="17540.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_DefinedBenefitPlanBenefitObligation" order="17820.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="sgu_DefinedBenefitPlanInterestCostIncludedInProjectedBenefitObligation" order="17960.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="sgu_DefinedBenefitPlanBenefitsPaidReducedFromProjectedBenefitObligation" order="18100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="sgu_DefinedBenefitPlanInvestmentAndOtherExpenses" order="18240.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="sgu_DefinedBenefitPlanAnticipatedExpenses" order="18380.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_DefinedBenefitPlanActuarialGainLoss" order="18520.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_DefinedBenefitPlanBenefitObligationPeriodIncreaseDecrease" order="18660.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_DefinedBenefitPlanFundedStatusOfPlan" order="18940.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTaxAbstract" order="21350.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="sgu_DefinedBenefitDifferenceBetweenActualAndExpectedReturnOnPlanAssets" order="21630.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax" order="21770.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax" order="21910.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" order="22050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossAfterTaxAbstract" order="23340.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax" order="23620.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureFairValuesAndPercentageOfCompanySPensionPlanAssetsByAssetCategoryDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureFairValuesAndPercentageOfCompanySPensionPlanAssetsByAssetCategoryDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureFairValuesAndPercentageOfCompanySPensionPlanAssetsByAssetCategoryDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:type="locator" xlink:label="us-gaap_FairValueInputsLevel1Member" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:type="locator" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsMember" xlink:type="locator" xlink:label="us-gaap_CashAndCashEquivalentsMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_InternationalEquityMember" xlink:type="locator" xlink:label="sgu_InternationalEquityMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_LargeCapEquitiesMember" xlink:type="locator" xlink:label="sgu_LargeCapEquitiesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BondsMember" xlink:type="locator" xlink:label="us-gaap_BondsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanAssetCategoriesDomain" xlink:type="locator" xlink:label="us-gaap_PlanAssetCategoriesDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanDisclosureLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:to="us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:to="us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:to="us-gaap_PlanAssetCategoriesDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PlanAssetCategoriesDomain" xlink:to="us-gaap_BondsMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PlanAssetCategoriesDomain" xlink:to="sgu_LargeCapEquitiesMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PlanAssetCategoriesDomain" xlink:to="sgu_InternationalEquityMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PlanAssetCategoriesDomain" xlink:to="us-gaap_CashAndCashEquivalentsMember" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:to="us-gaap_FairValueByFairValueHierarchyLevelAxis" order="10160.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="us-gaap_FairValueInputsLevel1Member" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:to="us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" order="10260.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:to="us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations" order="10440.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureIncomeTaxesAdditionalInformationDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureIncomeTaxesAdditionalInformationDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureIncomeTaxesAdditionalInformationDetail">
    <link:loc xlink:href="sgu-20200930.xsd#sgu_IncomeTaxExaminationYearsOpenForExamination" xlink:type="locator" xlink:label="sgu_IncomeTaxExaminationYearsOpenForExamination" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate" xlink:type="locator" xlink:label="us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLossCarryforwardsExpirationDate" xlink:type="locator" xlink:label="us-gaap_OperatingLossCarryforwardsExpirationDate" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLossCarryforwards" xlink:type="locator" xlink:label="us-gaap_OperatingLossCarryforwards" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:type="locator" xlink:label="us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:type="locator" xlink:label="us-gaap_IncomeTaxDisclosureAbstract" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:type="locator" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxCutsAndJobsActOf2017ChangeInTaxRateIncomeTaxExpenseBenefit" xlink:type="locator" xlink:label="us-gaap_TaxCutsAndJobsActOf2017ChangeInTaxRateIncomeTaxExpenseBenefit" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_TaxCutsAndJobsActPercentageOfDepreciationForFixedAssets" xlink:type="locator" xlink:label="sgu_TaxCutsAndJobsActPercentageOfDepreciationForFixedAssets" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CorporateIncomeTaxRate" xlink:type="locator" xlink:label="sgu_CorporateIncomeTaxRate" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsNet" xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsNet" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DeferralPaymentOfSocialSecurityTaxes" xlink:type="locator" xlink:label="sgu_DeferralPaymentOfSocialSecurityTaxes" />
    <link:loc xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_NJ" xlink:type="locator" xlink:label="stpr_NJ" />
    <link:loc xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_PA" xlink:type="locator" xlink:label="stpr_PA" />
    <link:loc xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_CT" xlink:type="locator" xlink:label="stpr_CT" />
    <link:loc xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_NY" xlink:type="locator" xlink:label="stpr_NY" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:type="locator" xlink:label="srt_MaximumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:type="locator" xlink:label="srt_MinimumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:type="locator" xlink:label="srt_RangeMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:type="locator" xlink:label="srt_RangeAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember" xlink:type="locator" xlink:label="us-gaap_StateAndLocalJurisdictionMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxYear2018Member" xlink:type="locator" xlink:label="us-gaap_TaxYear2018Member" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxYear2017Member" xlink:type="locator" xlink:label="us-gaap_TaxYear2017Member" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxPeriodDomain" xlink:type="locator" xlink:label="us-gaap_TaxPeriodDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxPeriodDomain" xlink:type="locator" xlink:label="us-gaap_TaxPeriodDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxPeriodAxis" xlink:type="locator" xlink:label="us-gaap_TaxPeriodAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_FederalMember" xlink:type="locator" xlink:label="sgu_FederalMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:type="locator" xlink:label="us-gaap_IncomeTaxAuthorityDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:type="locator" xlink:label="us-gaap_IncomeTaxAuthorityDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis" xlink:type="locator" xlink:label="us-gaap_IncomeTaxAuthorityAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CoronavirusAidReliefAndEconomicSecurityActMember" xlink:type="locator" xlink:label="sgu_CoronavirusAidReliefAndEconomicSecurityActMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EnvironmentalRemediationContingencyDomain" xlink:type="locator" xlink:label="us-gaap_EnvironmentalRemediationContingencyDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EnvironmentalRemediationContingencyDomain" xlink:type="locator" xlink:label="us-gaap_EnvironmentalRemediationContingencyDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EnvironmentalRemediationContingencyAxis" xlink:type="locator" xlink:label="us-gaap_EnvironmentalRemediationContingencyAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_IncomeTaxDisclosureTable" xlink:type="locator" xlink:label="sgu_IncomeTaxDisclosureTable" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_IncomeTaxDisclosureLineItems" xlink:type="locator" xlink:label="sgu_IncomeTaxDisclosureLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="sgu_IncomeTaxDisclosureLineItems" xlink:to="sgu_IncomeTaxDisclosureTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_IncomeTaxDisclosureTable" xlink:to="us-gaap_EnvironmentalRemediationContingencyAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_EnvironmentalRemediationContingencyAxis" xlink:to="us-gaap_EnvironmentalRemediationContingencyDomain_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_EnvironmentalRemediationContingencyAxis" xlink:to="us-gaap_EnvironmentalRemediationContingencyDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EnvironmentalRemediationContingencyDomain" xlink:to="sgu_CoronavirusAidReliefAndEconomicSecurityActMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_IncomeTaxDisclosureTable" xlink:to="us-gaap_IncomeTaxAuthorityAxis" order="10120.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_IncomeTaxAuthorityAxis" xlink:to="us-gaap_IncomeTaxAuthorityDomain_2" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_IncomeTaxAuthorityAxis" xlink:to="us-gaap_IncomeTaxAuthorityDomain" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeTaxAuthorityDomain" xlink:to="sgu_FederalMember" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_IncomeTaxDisclosureTable" xlink:to="us-gaap_TaxPeriodAxis" order="10200.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_TaxPeriodAxis" xlink:to="us-gaap_TaxPeriodDomain_2" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_TaxPeriodAxis" xlink:to="us-gaap_TaxPeriodDomain" order="10230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TaxPeriodDomain" xlink:to="us-gaap_TaxYear2017Member" order="10250.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TaxPeriodDomain" xlink:to="us-gaap_TaxYear2018Member" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeTaxAuthorityDomain" xlink:to="us-gaap_StateAndLocalJurisdictionMember" order="10330.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="sgu_IncomeTaxDisclosureTable" xlink:to="srt_RangeAxis" order="10380.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="10410.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MinimumMember" order="10430.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MaximumMember" order="10450.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeTaxAuthorityDomain" xlink:to="stpr_NY" order="10530.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeTaxAuthorityDomain" xlink:to="stpr_CT" order="10550.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeTaxAuthorityDomain" xlink:to="stpr_PA" order="10570.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeTaxAuthorityDomain" xlink:to="stpr_NJ" order="10590.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_IncomeTaxDisclosureLineItems" xlink:to="sgu_DeferralPaymentOfSocialSecurityTaxes" order="10620.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_DeferredTaxAssetsNet" order="10640.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_IncomeTaxDisclosureLineItems" xlink:to="sgu_CorporateIncomeTaxRate" order="10690.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_IncomeTaxDisclosureLineItems" xlink:to="sgu_TaxCutsAndJobsActPercentageOfDepreciationForFixedAssets" order="10730.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_TaxCutsAndJobsActOf2017ChangeInTaxRateIncomeTaxExpenseBenefit" order="10750.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" order="10800.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" order="10920.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_IncomeTaxDisclosureAbstract" order="11070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" order="11150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_OperatingLossCarryforwards" order="11220.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_OperatingLossCarryforwardsExpirationDate" order="11240.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate" order="11310.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="sgu_IncomeTaxDisclosureLineItems" xlink:to="sgu_IncomeTaxExaminationYearsOpenForExamination" order="11400.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureLeasesAdditionalInformationDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureLeasesAdditionalInformationDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureLeasesAdditionalInformationDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseExpense" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseExpense" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MinimumInitialOrRemainingOperatingLeaseTerm" xlink:type="locator" xlink:label="sgu_MinimumInitialOrRemainingOperatingLeaseTerm" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_LesseeOperatingLeaseOptionToExtendTerm" xlink:type="locator" xlink:label="sgu_LesseeOperatingLeaseOptionToExtendTerm" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseTermOfContract" xlink:type="locator" xlink:label="us-gaap_LesseeOperatingLeaseTermOfContract" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_OperatingLeaseExpirationYear" xlink:type="locator" xlink:label="sgu_OperatingLeaseExpirationYear" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:type="locator" xlink:label="srt_MaximumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:type="locator" xlink:label="srt_MinimumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:type="locator" xlink:label="srt_RangeMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:type="locator" xlink:label="srt_RangeAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable" xlink:type="locator" xlink:label="us-gaap_LesseeLeaseDescriptionTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems" xlink:type="locator" xlink:label="us-gaap_LesseeLeaseDescriptionLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems" xlink:to="us-gaap_LesseeLeaseDescriptionTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_LesseeLeaseDescriptionTable" xlink:to="srt_RangeAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MinimumMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MaximumMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems" xlink:to="sgu_OperatingLeaseExpirationYear" order="10200.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems" xlink:to="us-gaap_LesseeOperatingLeaseTermOfContract" order="10240.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems" xlink:to="sgu_LesseeOperatingLeaseOptionToExtendTerm" order="10300.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems" xlink:to="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" order="10350.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems" xlink:to="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" order="10370.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems" xlink:to="sgu_MinimumInitialOrRemainingOperatingLeaseTerm" order="10420.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems" xlink:to="us-gaap_OperatingLeaseExpense" order="10470.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureSubsequentEventsAdditionalInformationDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureSubsequentEventsAdditionalInformationDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureSubsequentEventsAdditionalInformationDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromSaleOfOilAndGasPropertyAndEquipment" xlink:type="locator" xlink:label="us-gaap_ProceedsFromSaleOfOilAndGasPropertyAndEquipment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodValue" xlink:type="locator" xlink:label="us-gaap_StockRepurchasedDuringPeriodValue" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodShares" xlink:type="locator" xlink:label="us-gaap_StockRepurchasedDuringPeriodShares" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_AveragePricePaidPerUnit" xlink:type="locator" xlink:label="sgu_AveragePricePaidPerUnit" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:type="locator" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DividendsPayableDateOfRecordDayMonthAndYear" xlink:type="locator" xlink:label="us-gaap_DividendsPayableDateOfRecordDayMonthAndYear" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DividendPayableDateToBePaidDayMonthAndYear" xlink:type="locator" xlink:label="us-gaap_DividendPayableDateToBePaidDayMonthAndYear" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_IncentiveDistributionsToManagement" xlink:type="locator" xlink:label="sgu_IncentiveDistributionsToManagement" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_IncentiveDistributionToGeneralPartner" xlink:type="locator" xlink:label="sgu_IncentiveDistributionToGeneralPartner" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GeneralPartnersCapitalAccountDistributionAmount" xlink:type="locator" xlink:label="us-gaap_GeneralPartnersCapitalAccountDistributionAmount" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountDistributionAmount" xlink:type="locator" xlink:label="us-gaap_LimitedPartnersCapitalAccountDistributionAmount" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MinimumDividendDistributionPerUnit" xlink:type="locator" xlink:label="sgu_MinimumDividendDistributionPerUnit" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_PartnersCapitalProjectedDistributionAmountOnAnnualizedBasisPerShare" xlink:type="locator" xlink:label="sgu_PartnersCapitalProjectedDistributionAmountOnAnnualizedBasisPerShare" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PartnersCapitalDistributionAmountPerShare" xlink:type="locator" xlink:label="us-gaap_PartnersCapitalDistributionAmountPerShare" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OilAndGasPropertiesMember" xlink:type="locator" xlink:label="us-gaap_OilAndGasPropertiesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_MoabPartnersLPMember" xlink:type="locator" xlink:label="sgu_MoabPartnersLPMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:type="locator" xlink:label="us-gaap_RelatedPartyDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_UnitPurchaseAgreementMember" xlink:type="locator" xlink:label="sgu_UnitPurchaseAgreementMember" />
    <link:loc xlink:href="sgu-20200930.xsd#sgu_CommonStockRepurchaseProgramMember" xlink:type="locator" xlink:label="sgu_CommonStockRepurchaseProgramMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain" xlink:type="locator" xlink:label="us-gaap_ShareRepurchaseProgramDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramAxis" xlink:type="locator" xlink:label="us-gaap_ShareRepurchaseProgramAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DividendDeclaredMember" xlink:type="locator" xlink:label="us-gaap_DividendDeclaredMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DividendsDomain" xlink:type="locator" xlink:label="us-gaap_DividendsDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DividendsDomain" xlink:type="locator" xlink:label="us-gaap_DividendsDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DividendsAxis" xlink:type="locator" xlink:label="us-gaap_DividendsAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventMember" xlink:type="locator" xlink:label="us-gaap_SubsequentEventMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:type="locator" xlink:label="us-gaap_SubsequentEventTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:type="locator" xlink:label="us-gaap_SubsequentEventTypeAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTable" xlink:type="locator" xlink:label="us-gaap_SubsequentEventTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventLineItems" xlink:type="locator" xlink:label="us-gaap_SubsequentEventLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_SubsequentEventTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_SubsequentEventTable" xlink:to="us-gaap_SubsequentEventTypeAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_SubsequentEventTypeAxis" xlink:to="us-gaap_SubsequentEventTypeDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventTypeDomain" xlink:to="us-gaap_SubsequentEventMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_SubsequentEventTable" xlink:to="us-gaap_DividendsAxis" order="10100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_DividendsAxis" xlink:to="us-gaap_DividendsDomain_2" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DividendsAxis" xlink:to="us-gaap_DividendsDomain" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DividendsDomain" xlink:to="us-gaap_DividendDeclaredMember" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_SubsequentEventTable" xlink:to="us-gaap_ShareRepurchaseProgramAxis" order="10220.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ShareRepurchaseProgramAxis" xlink:to="us-gaap_ShareRepurchaseProgramDomain" order="10250.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareRepurchaseProgramDomain" xlink:to="sgu_CommonStockRepurchaseProgramMember" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareRepurchaseProgramDomain" xlink:to="sgu_UnitPurchaseAgreementMember" order="10410.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_SubsequentEventTable" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" order="10440.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain" order="10470.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="sgu_MoabPartnersLPMember" order="10490.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_SubsequentEventTable" xlink:to="us-gaap_PropertyPlantAndEquipmentByTypeAxis" order="10520.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain" order="10550.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_OilAndGasPropertiesMember" order="10570.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_PartnersCapitalDistributionAmountPerShare" order="10660.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="sgu_PartnersCapitalProjectedDistributionAmountOnAnnualizedBasisPerShare" order="10680.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="sgu_MinimumDividendDistributionPerUnit" order="10700.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_LimitedPartnersCapitalAccountDistributionAmount" order="10720.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_GeneralPartnersCapitalAccountDistributionAmount" order="10740.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="sgu_IncentiveDistributionToGeneralPartner" order="10760.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="sgu_IncentiveDistributionsToManagement" order="10780.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_DividendPayableDateToBePaidDayMonthAndYear" order="10800.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_DividendsPayableDateOfRecordDayMonthAndYear" order="10820.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" order="10870.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="sgu_AveragePricePaidPerUnit" order="10890.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_StockRepurchasedDuringPeriodShares" order="10940.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_StockRepurchasedDuringPeriodValue" order="10960.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_ProceedsFromSaleOfOilAndGasPropertyAndEquipment" order="11010.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureCondensedFinancialInformationOfRegistrantBalanceSheetsDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureCondensedFinancialInformationOfRegistrantBalanceSheetsDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureCondensedFinancialInformationOfRegistrantBalanceSheetsDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:type="locator" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PartnersCapital" xlink:type="locator" xlink:label="us-gaap_PartnersCapital" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:type="locator" xlink:label="us-gaap_LiabilitiesCurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:type="locator" xlink:label="us-gaap_AccruedLiabilitiesCurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:type="locator" xlink:label="us-gaap_LiabilitiesCurrentAbstract" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:type="locator" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Assets" xlink:type="locator" xlink:label="us-gaap_Assets" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestments" xlink:type="locator" xlink:label="us-gaap_EquityMethodInvestments" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsCurrent" xlink:type="locator" xlink:label="us-gaap_AssetsCurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:type="locator" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:type="locator" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:type="locator" xlink:label="us-gaap_AssetsCurrentAbstract" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsAbstract" xlink:type="locator" xlink:label="us-gaap_AssetsAbstract" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ParentCompanyMember" xlink:type="locator" xlink:label="srt_ParentCompanyMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:type="locator" xlink:label="srt_ConsolidatedEntitiesDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:type="locator" xlink:label="srt_ConsolidatedEntitiesAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CondensedBalanceSheetStatementTable" xlink:type="locator" xlink:label="srt_CondensedBalanceSheetStatementTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CondensedBalanceSheetStatementsCaptionsLineItems" xlink:type="locator" xlink:label="srt_CondensedBalanceSheetStatementsCaptionsLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="srt_CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="srt_CondensedBalanceSheetStatementTable" order="10030.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="srt_CondensedBalanceSheetStatementTable" xlink:to="srt_ConsolidatedEntitiesAxis" order="10060.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_ConsolidatedEntitiesAxis" xlink:to="srt_ConsolidatedEntitiesDomain" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ConsolidatedEntitiesDomain" xlink:to="srt_ParentCompanyMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="us-gaap_AssetsAbstract" order="10140.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AssetsAbstract" xlink:to="us-gaap_AssetsCurrentAbstract" order="10220.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue" order="10300.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" order="10340.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_AssetsCurrent" order="10380.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AssetsAbstract" xlink:to="us-gaap_EquityMethodInvestments" order="10420.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AssetsAbstract" xlink:to="us-gaap_Assets" order="10460.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="us-gaap_LiabilitiesAndStockholdersEquityAbstract" order="10500.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:to="us-gaap_LiabilitiesCurrentAbstract" order="10580.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_AccruedLiabilitiesCurrent" order="10660.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_LiabilitiesCurrent" order="10700.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:to="us-gaap_PartnersCapital" order="10740.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:to="us-gaap_LiabilitiesAndStockholdersEquity" order="10780.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureCondensedFinancialInformationOfRegistrantOfOperationsDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureCondensedFinancialInformationOfRegistrantOfOperationsDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureCondensedFinancialInformationOfRegistrantOfOperationsDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss" xlink:type="locator" xlink:label="us-gaap_NetIncomeLoss" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:type="locator" xlink:label="us-gaap_IncomeLossFromEquityMethodInvestments" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:type="locator" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:type="locator" xlink:label="us-gaap_OperatingIncomeLoss" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:type="locator" xlink:label="us-gaap_GeneralAndAdministrativeExpense" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:type="locator" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ParentCompanyMember" xlink:type="locator" xlink:label="srt_ParentCompanyMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:type="locator" xlink:label="srt_ConsolidatedEntitiesDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:type="locator" xlink:label="srt_ConsolidatedEntitiesAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CondensedIncomeStatementTable" xlink:type="locator" xlink:label="srt_CondensedIncomeStatementTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CondensedIncomeStatementsCaptionsLineItems" xlink:type="locator" xlink:label="srt_CondensedIncomeStatementsCaptionsLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="srt_CondensedIncomeStatementsCaptionsLineItems" xlink:to="srt_CondensedIncomeStatementTable" order="10030.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="srt_CondensedIncomeStatementTable" xlink:to="srt_ConsolidatedEntitiesAxis" order="10060.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_ConsolidatedEntitiesAxis" xlink:to="srt_ConsolidatedEntitiesDomain" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ConsolidatedEntitiesDomain" xlink:to="srt_ParentCompanyMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_CondensedIncomeStatementsCaptionsLineItems" xlink:to="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" order="10140.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_CondensedIncomeStatementsCaptionsLineItems" xlink:to="us-gaap_GeneralAndAdministrativeExpense" order="10200.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_CondensedIncomeStatementsCaptionsLineItems" xlink:to="us-gaap_OperatingIncomeLoss" order="10260.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_CondensedIncomeStatementsCaptionsLineItems" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" order="10320.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_CondensedIncomeStatementsCaptionsLineItems" xlink:to="us-gaap_IncomeLossFromEquityMethodInvestments" order="10380.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_CondensedIncomeStatementsCaptionsLineItems" xlink:to="us-gaap_NetIncomeLoss" order="10440.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureCondensedFinancialInformationOfRegistrantStatementsOfCashFlowsDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureCondensedFinancialInformationOfRegistrantStatementsOfCashFlowsDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureCondensedFinancialInformationOfRegistrantStatementsOfCashFlowsDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:type="locator" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:type="locator" xlink:label="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsForRepurchaseOfEquity" xlink:type="locator" xlink:label="us-gaap_PaymentsForRepurchaseOfEquity" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsOfDividends" xlink:type="locator" xlink:label="us-gaap_PaymentsOfDividends" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ParentCompanyMember" xlink:type="locator" xlink:label="srt_ParentCompanyMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:type="locator" xlink:label="srt_ConsolidatedEntitiesDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:type="locator" xlink:label="srt_ConsolidatedEntitiesAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CondensedCashFlowStatementTable" xlink:type="locator" xlink:label="srt_CondensedCashFlowStatementTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CondensedCashFlowStatementsCaptionsLineItems" xlink:type="locator" xlink:label="srt_CondensedCashFlowStatementsCaptionsLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="srt_CondensedCashFlowStatementsCaptionsLineItems" xlink:to="srt_CondensedCashFlowStatementTable" order="10040.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="srt_CondensedCashFlowStatementTable" xlink:to="srt_ConsolidatedEntitiesAxis" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_ConsolidatedEntitiesAxis" xlink:to="srt_ConsolidatedEntitiesDomain" order="10100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ConsolidatedEntitiesDomain" xlink:to="srt_ParentCompanyMember" order="10120.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_CondensedCashFlowStatementsCaptionsLineItems" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivities" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_CondensedCashFlowStatementsCaptionsLineItems" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" order="10330.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivities" order="10450.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_CondensedCashFlowStatementsCaptionsLineItems" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" order="10510.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="us-gaap_PaymentsOfDividends" order="10630.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="us-gaap_PaymentsForRepurchaseOfEquity" order="10690.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivities" order="10750.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_CondensedCashFlowStatementsCaptionsLineItems" xlink:to="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" order="10810.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_CondensedCashFlowStatementsCaptionsLineItems" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue" order="10870.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureCondensedFinancialInformationOfRegistrantStatementsOfCashFlowsParentheticalDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureCondensedFinancialInformationOfRegistrantStatementsOfCashFlowsParentheticalDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureCondensedFinancialInformationOfRegistrantStatementsOfCashFlowsParentheticalDetail">
    <link:loc xlink:href="sgu-20200930.xsd#sgu_DistributionFromSubsidiaries" xlink:type="locator" xlink:label="sgu_DistributionFromSubsidiaries" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ParentCompanyMember" xlink:type="locator" xlink:label="srt_ParentCompanyMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:type="locator" xlink:label="srt_ConsolidatedEntitiesDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:type="locator" xlink:label="srt_ConsolidatedEntitiesAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CondensedCashFlowStatementTable" xlink:type="locator" xlink:label="srt_CondensedCashFlowStatementTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CondensedCashFlowStatementsCaptionsLineItems" xlink:type="locator" xlink:label="srt_CondensedCashFlowStatementsCaptionsLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="srt_CondensedCashFlowStatementsCaptionsLineItems" xlink:to="srt_CondensedCashFlowStatementTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="srt_CondensedCashFlowStatementTable" xlink:to="srt_ConsolidatedEntitiesAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_ConsolidatedEntitiesAxis" xlink:to="srt_ConsolidatedEntitiesDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ConsolidatedEntitiesDomain" xlink:to="srt_ParentCompanyMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_CondensedCashFlowStatementsCaptionsLineItems" xlink:to="sgu_DistributionFromSubsidiaries" order="10120.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureValuationAndQualifyingAccountsDetail" xlink:href="sgu-20200930.xsd#Role_DisclosureValuationAndQualifyingAccountsDetail" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.stargrouplp.com/20200930/taxonomy/role/DisclosureValuationAndQualifyingAccountsDetail">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts" xlink:type="locator" xlink:label="us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense" xlink:type="locator" xlink:label="us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowancesAndReservesBalance" xlink:type="locator" xlink:label="us-gaap_ValuationAllowancesAndReservesBalance" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllowanceForCreditLossMember" xlink:type="locator" xlink:label="us-gaap_AllowanceForCreditLossMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDomain" xlink:type="locator" xlink:label="us-gaap_ValuationAllowancesAndReservesDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDomain" xlink:type="locator" xlink:label="us-gaap_ValuationAllowancesAndReservesDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowancesAndReservesTypeAxis" xlink:type="locator" xlink:label="us-gaap_ValuationAllowancesAndReservesTypeAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ValuationAndQualifyingAccountsDisclosureTable" xlink:type="locator" xlink:label="srt_ValuationAndQualifyingAccountsDisclosureTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ValuationAndQualifyingAccountsDisclosureLineItems" xlink:type="locator" xlink:label="srt_ValuationAndQualifyingAccountsDisclosureLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="srt_ValuationAndQualifyingAccountsDisclosureLineItems" xlink:to="srt_ValuationAndQualifyingAccountsDisclosureTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="srt_ValuationAndQualifyingAccountsDisclosureTable" xlink:to="us-gaap_ValuationAllowancesAndReservesTypeAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ValuationAllowancesAndReservesTypeAxis" xlink:to="us-gaap_ValuationAllowancesAndReservesDomain_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ValuationAllowancesAndReservesTypeAxis" xlink:to="us-gaap_ValuationAllowancesAndReservesDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ValuationAllowancesAndReservesDomain" xlink:to="us-gaap_AllowanceForCreditLossMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ValuationAndQualifyingAccountsDisclosureLineItems" xlink:to="us-gaap_ValuationAllowancesAndReservesBalance" order="10120.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ValuationAndQualifyingAccountsDisclosureLineItems" xlink:to="us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense" order="10180.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ValuationAndQualifyingAccountsDisclosureLineItems" xlink:to="us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts" order="10240.00" priority="2" use="optional" />
  </link:definitionLink>
</link:linkbase>
