<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<link:linkbase xmlns:ns6="http://www.sec.gov/edgar/sccommon" xmlns:ns5="http://xbrl.org/2006/xbrldi" xmlns:ns8="http://www.sec.gov/edgar/coregsc" xmlns:ns7="http://www.sec.gov/edgar/singlefilersc" xmlns:ns9="http://www.sec.gov/edgar/common" xmlns:ns11="http://www.sec.gov/edgar/feecommon" xmlns:ns10="http://www.sec.gov/edgar/bulkfiling" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:ns4="http://www.xbrl.org/2003/instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:ns3="http://www.xbrl.org/2003/XLink">
    <link:roleRef roleURI="http://xbrl.sec.gov/oef/role/SeriesOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#SeriesOnly"/>
    <link:roleRef roleURI="http://xbrl.sec.gov/oef/role/ClassOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#ClassOnly"/>
    <link:roleRef roleURI="http://xbrl.sec.gov/rr/role/RiskOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#RiskOnly"/>
    <link:roleRef roleURI="http://xbrl.sec.gov/rr/role/PerformanceMeasureOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#PerformanceMeasureOnly"/>
    <link:roleRef roleURI="http://www.fidelity.com/role/DocumentInformation" xlink:type="simple" xlink:href="fmr-20260929.xsd#role_DocumentInformation"/>
    <link:roleRef roleURI="http://www.fidelity.com/role/RiskSummaryS000055837_FidelityCommodityStrategyFund-RetailPRO" xlink:type="simple" xlink:href="fmr-20260929.xsd#role_RiskSummaryS000055837_FidelityCommodityStrategyFund-RetailPRO"/>
    <link:roleRef roleURI="http://www.fidelity.com/role/DisclosureDetailS000055837_FidelityCommodityStrategyFund-RetailPRO" xlink:type="simple" xlink:href="fmr-20260929.xsd#role_DisclosureDetailS000055837_FidelityCommodityStrategyFund-RetailPRO"/>
    <link:roleRef roleURI="http://www.fidelity.com/role/RiskSummaryS000063840_FidelitySAIInflation-FocusedFund-PRO" xlink:type="simple" xlink:href="fmr-20260929.xsd#role_RiskSummaryS000063840_FidelitySAIInflation-FocusedFund-PRO"/>
    <link:roleRef roleURI="http://www.fidelity.com/role/DisclosureDetailS000063840_FidelitySAIInflation-FocusedFund-PRO" xlink:type="simple" xlink:href="fmr-20260929.xsd#role_DisclosureDetailS000063840_FidelitySAIInflation-FocusedFund-PRO"/>
    <link:roleRef roleURI="http://www.fidelity.com/role/RiskSummaryS000042145_FidelitySeriesCommodityStrategyFund-PRO" xlink:type="simple" xlink:href="fmr-20260929.xsd#role_RiskSummaryS000042145_FidelitySeriesCommodityStrategyFund-PRO"/>
    <link:roleRef roleURI="http://www.fidelity.com/role/DisclosureDetailS000042145_FidelitySeriesCommodityStrategyFund-PRO" xlink:type="simple" xlink:href="fmr-20260929.xsd#role_DisclosureDetailS000042145_FidelitySeriesCommodityStrategyFund-PRO"/>
    <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
    <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
    <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
    <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
    <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/SeriesOnly" xlink:title="050020 - Document - Series">
        <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis"/>
        <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain" xlink:label="EntityDomain"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_S000063840Member" xlink:label="fmr_S000063840Member"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="fmr_S000063840Member" order="10.1"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_S000042145Member" xlink:label="fmr_S000042145Member"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="fmr_S000042145Member" order="10.2"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_S000055837Member" xlink:label="fmr_S000055837Member"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="fmr_S000055837Member" order="10.3"/>
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/ClassOnly" xlink:title="050030 - Document - Class">
        <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_ShareClassDomain" xlink:label="ShareClassDomain"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_C000206762Member" xlink:label="fmr_C000206762Member"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_C000130874Member" xlink:label="fmr_C000130874Member"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_C000175832Member" xlink:label="fmr_C000175832Member"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="fmr_C000206762Member" order="2"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="fmr_C000130874Member" order="3"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="fmr_C000175832Member" order="4"/>
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/RiskOnly" xlink:title="050010 - Document - Risk">
        <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_AllRisksMember" xlink:label="AllRisksMember"/>
        <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_RiskAxis" xlink:label="RiskAxis"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_LeverageRiskMember" xlink:label="LeverageRiskMember"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="LeverageRiskMember" order="500"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_IssuerSpecificChangesMember" xlink:label="IssuerSpecificChangesMember"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="IssuerSpecificChangesMember" order="500.1"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_FinancialServicesExposureMember" xlink:label="FinancialServicesExposureMember"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="FinancialServicesExposureMember" order="500.2"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_SubsidiaryRiskMember" xlink:label="SubsidiaryRiskMember"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="SubsidiaryRiskMember" order="500.3"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_CommodityFuturesMember" xlink:label="CommodityFuturesMember"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="CommodityFuturesMember" order="500.4"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_CorrelationToIndexMember" xlink:label="CorrelationToIndexMember"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="CorrelationToIndexMember" order="500.5"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_InterestRateChangesMember" xlink:label="InterestRateChangesMember"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="InterestRateChangesMember" order="500.6"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_CommodityLinkedInvestingMember" xlink:label="CommodityLinkedInvestingMember"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="CommodityLinkedInvestingMember" order="500.7"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_ForeignExposureMember" xlink:label="ForeignExposureMember"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="ForeignExposureMember" order="500.8"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_InvestingForInflationProtectionMember" xlink:label="InvestingForInflationProtectionMember"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="InvestingForInflationProtectionMember" order="500.9"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_PassiveManagementRiskMember" xlink:label="PassiveManagementRiskMember"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="PassiveManagementRiskMember" order="501.0"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_PrepaymentMember" xlink:label="PrepaymentMember"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="PrepaymentMember" order="501.1"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_USGovernmentObligationsRiskMember" xlink:label="USGovernmentObligationsRiskMember"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="USGovernmentObligationsRiskMember" order="501.2"/>
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/PerformanceMeasureOnly" xlink:title="050040 - Document - Performance Measure">
        <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_PerformanceMeasureDomain" xlink:label="PerformanceMeasureDomain"/>
        <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_AfterTaxesOnDistributionsMember" xlink:label="AfterTaxesOnDistributionsMember"/>
        <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_AfterTaxesOnDistributionsAndSalesMember" xlink:label="AfterTaxesOnDistributionsAndSalesMember"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_IndexIXTJXMember" xlink:label="fmr_IndexIXTJXMember"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_IndexIXTQPMember" xlink:label="fmr_IndexIXTQPMember"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_IndexMS159Member" xlink:label="fmr_IndexMS159Member"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_IndexIXRVSMember" xlink:label="fmr_IndexIXRVSMember"/>
        <link:loc xlink:type="locator" xlink:href="fmr-20260929.xsd#fmr_IndexIXR7YMember" xlink:label="fmr_IndexIXR7YMember"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="fmr_IndexIXTJXMember" order="5"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="fmr_IndexIXTQPMember" order="6"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="fmr_IndexMS159Member" order="7"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="fmr_IndexIXRVSMember" order="8"/>
        <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="fmr_IndexIXR7YMember" order="9"/>
    </link:definitionLink>
</link:linkbase>
