<?xml version="1.0" encoding="utf-8"?>
<!--XBRL document created with Toppan Merrill Bridge  10.9.0.3 -->
<!--Based on XBRL 2.1-->
<!--Created on: 3/27/2025 4:21:10 PM-->
<!--Modified on: 3/27/2025 4:21:10 PM-->
<link:linkbase 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" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink">
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DocumentDocumentAndEntityInformation" roleURI="http://www.fortunasilver.com/role/DocumentDocumentAndEntityInformation" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#StatementConsolidatedStatementsOfCashFlows" roleURI="http://www.fortunasilver.com/role/StatementConsolidatedStatementsOfCashFlows" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#StatementConsolidatedStatementsOfChangesInEquity" roleURI="http://www.fortunasilver.com/role/StatementConsolidatedStatementsOfChangesInEquity" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureShareBasedPaymentsTables" roleURI="http://www.fortunasilver.com/role/DisclosureShareBasedPaymentsTables" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureManagementOfFinancialRiskTables" roleURI="http://www.fortunasilver.com/role/DisclosureManagementOfFinancialRiskTables" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureNatureOfOperationsDetails" roleURI="http://www.fortunasilver.com/role/DisclosureNatureOfOperationsDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureMaterialAccountingPoliciesNarrativeDetails" roleURI="http://www.fortunasilver.com/role/DisclosureMaterialAccountingPoliciesNarrativeDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureMaterialAccountingPoliciesDisclosureOfSubsidiariesDetails" roleURI="http://www.fortunasilver.com/role/DisclosureMaterialAccountingPoliciesDisclosureOfSubsidiariesDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureMaterialAccountingPoliciesScheduleRelatedToPropertyPlantAndEquipmentDetails" roleURI="http://www.fortunasilver.com/role/DisclosureMaterialAccountingPoliciesScheduleRelatedToPropertyPlantAndEquipmentDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureUseOfEstimatesAssumptionsAndJudgementsNarrativeDetails" roleURI="http://www.fortunasilver.com/role/DisclosureUseOfEstimatesAssumptionsAndJudgementsNarrativeDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureTradeAndOtherReceivablesScheduleOfTradeAndOtherReceivablesDetails" roleURI="http://www.fortunasilver.com/role/DisclosureTradeAndOtherReceivablesScheduleOfTradeAndOtherReceivablesDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureInventoriesScheduleOfInventoriesDetails" roleURI="http://www.fortunasilver.com/role/DisclosureInventoriesScheduleOfInventoriesDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureMineralPropertiesAndPropertyPlantAndEquipmentNarrativeDetails" roleURI="http://www.fortunasilver.com/role/DisclosureMineralPropertiesAndPropertyPlantAndEquipmentNarrativeDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureMineralPropertiesAndPropertyPlantAndEquipmentScheduleRelatedToPropertyPlantAndEquipmentDetails" roleURI="http://www.fortunasilver.com/role/DisclosureMineralPropertiesAndPropertyPlantAndEquipmentScheduleRelatedToPropertyPlantAndEquipmentDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureOtherNonCurrentAssetsScheduleOfOtherAssetsDetails" roleURI="http://www.fortunasilver.com/role/DisclosureOtherNonCurrentAssetsScheduleOfOtherAssetsDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureTradeAndOtherPayablesScheduleOfTradeAndOtherPayablesDetails" roleURI="http://www.fortunasilver.com/role/DisclosureTradeAndOtherPayablesScheduleOfTradeAndOtherPayablesDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureLeaseObligationsScheduleOfLeaseObligationsDetails" roleURI="http://www.fortunasilver.com/role/DisclosureLeaseObligationsScheduleOfLeaseObligationsDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureDebtMovementInDebtDetails" roleURI="http://www.fortunasilver.com/role/DisclosureDebtMovementInDebtDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureDebt2024ConvertibleNotesDetails" roleURI="http://www.fortunasilver.com/role/DisclosureDebt2024ConvertibleNotesDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureDebt2019ConvertibleDebenturesDetails" roleURI="http://www.fortunasilver.com/role/DisclosureDebt2019ConvertibleDebenturesDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureDebtCreditFacilitiesDetails" roleURI="http://www.fortunasilver.com/role/DisclosureDebtCreditFacilitiesDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureOtherNonCurrentLiabilitiesScheduleOfOtherLiabilitiesDetails" roleURI="http://www.fortunasilver.com/role/DisclosureOtherNonCurrentLiabilitiesScheduleOfOtherLiabilitiesDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureClosureAndReclamationProvisionsScheduleOfClosureAndRehabilitationProvisionsDetails" roleURI="http://www.fortunasilver.com/role/DisclosureClosureAndReclamationProvisionsScheduleOfClosureAndRehabilitationProvisionsDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureClosureAndReclamationProvisionsScheduleOfEstimatesUsedInClosureAndRehabilitationProvisionsDetails" roleURI="http://www.fortunasilver.com/role/DisclosureClosureAndReclamationProvisionsScheduleOfEstimatesUsedInClosureAndRehabilitationProvisionsDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureShareBasedPaymentsNarrativeDetails" roleURI="http://www.fortunasilver.com/role/DisclosureShareBasedPaymentsNarrativeDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureShareBasedPaymentsScheduleOfOutstandingUnitsActivityDetails" roleURI="http://www.fortunasilver.com/role/DisclosureShareBasedPaymentsScheduleOfOutstandingUnitsActivityDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureShareBasedPaymentsScheduleOfOutstandingOptionActivityDetails" roleURI="http://www.fortunasilver.com/role/DisclosureShareBasedPaymentsScheduleOfOutstandingOptionActivityDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureSalesScheduleOfSalesByProductAndGeographicalAreaDetails" roleURI="http://www.fortunasilver.com/role/DisclosureSalesScheduleOfSalesByProductAndGeographicalAreaDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureSalesScheduleOfSalesByMajorCustomerDetails" roleURI="http://www.fortunasilver.com/role/DisclosureSalesScheduleOfSalesByMajorCustomerDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureOtherExpensesAdditionalInformationDetails" roleURI="http://www.fortunasilver.com/role/DisclosureOtherExpensesAdditionalInformationDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureInterestAndFinanceCostsNetDetails" roleURI="http://www.fortunasilver.com/role/DisclosureInterestAndFinanceCostsNetDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureIncomeTaxNarrativeDetails" roleURI="http://www.fortunasilver.com/role/DisclosureIncomeTaxNarrativeDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureIncomeTaxScheduleOfDeferredTaxAssetsAndLiabilitiesDetails" roleURI="http://www.fortunasilver.com/role/DisclosureIncomeTaxScheduleOfDeferredTaxAssetsAndLiabilitiesDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureIncomeTaxScheduleOfUnrecognizedDeductibleTemporaryDifferenceAndUnusedTaxLossesDetails" roleURI="http://www.fortunasilver.com/role/DisclosureIncomeTaxScheduleOfUnrecognizedDeductibleTemporaryDifferenceAndUnusedTaxLossesDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureIncomeTaxScheduleOfTaxLossesExpiryDatesDetails" roleURI="http://www.fortunasilver.com/role/DisclosureIncomeTaxScheduleOfTaxLossesExpiryDatesDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureSegmentedInformationScheduleOfSegmentedInformationDetails" roleURI="http://www.fortunasilver.com/role/DisclosureSegmentedInformationScheduleOfSegmentedInformationDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureFairValueMeasurementsScheduleOfFinancialAssetsAndFinancialLiabilitiesByCategoryDetails" roleURI="http://www.fortunasilver.com/role/DisclosureFairValueMeasurementsScheduleOfFinancialAssetsAndFinancialLiabilitiesByCategoryDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureFairValueMeasurementsScheduleOfFairValuesOfFinancialAssetsAndFinancialLiabilitiesDetails" roleURI="http://www.fortunasilver.com/role/DisclosureFairValueMeasurementsScheduleOfFairValuesOfFinancialAssetsAndFinancialLiabilitiesDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureFairValueMeasurementsScheduleOfFinancialAssetsAndFinancialLiabilitiesNotAlreadyMeasuredAtFairValueDetails" roleURI="http://www.fortunasilver.com/role/DisclosureFairValueMeasurementsScheduleOfFinancialAssetsAndFinancialLiabilitiesNotAlreadyMeasuredAtFairValueDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureManagementOfFinancialRiskScheduleOfCompanySMaximumExposureToCreditRiskDetails" roleURI="http://www.fortunasilver.com/role/DisclosureManagementOfFinancialRiskScheduleOfCompanySMaximumExposureToCreditRiskDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureManagementOfFinancialRiskScheduleOfCompanySLiquidityRiskDetails" roleURI="http://www.fortunasilver.com/role/DisclosureManagementOfFinancialRiskScheduleOfCompanySLiquidityRiskDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureManagementOfFinancialRiskDisclosureOfNatureAndExtentArisingFromFinancialInstrumentsCurrencyRiskDetails" roleURI="http://www.fortunasilver.com/role/DisclosureManagementOfFinancialRiskDisclosureOfNatureAndExtentArisingFromFinancialInstrumentsCurrencyRiskDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureManagementOfFinancialRiskDisclosureOfNatureAndExtentArisingFromFinancialInstrumentsCommodityPriceRiskDetails" roleURI="http://www.fortunasilver.com/role/DisclosureManagementOfFinancialRiskDisclosureOfNatureAndExtentArisingFromFinancialInstrumentsCommodityPriceRiskDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureSupplementalCashFlowInformationScheduleOfChangesInLiabilitiesArisingFromFinancingActivitiesDetails" roleURI="http://www.fortunasilver.com/role/DisclosureSupplementalCashFlowInformationScheduleOfChangesInLiabilitiesArisingFromFinancingActivitiesDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureNonControllingInterestsDetails" roleURI="http://www.fortunasilver.com/role/DisclosureNonControllingInterestsDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureNonControllingInterestsSummarizedFinancialStatementsDetails" roleURI="http://www.fortunasilver.com/role/DisclosureNonControllingInterestsSummarizedFinancialStatementsDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureContingenciesAndCapitalCommitmentsNarrativeDetails" roleURI="http://www.fortunasilver.com/role/DisclosureContingenciesAndCapitalCommitmentsNarrativeDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureImpairmentNarrativeDetails" roleURI="http://www.fortunasilver.com/role/DisclosureImpairmentNarrativeDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureSubsequentEventsDetails" roleURI="http://www.fortunasilver.com/role/DisclosureSubsequentEventsDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <link:roleRef roleURI="http://www.fortunasilver.com/role/DisclosureStandardAndCustomAxisDomainDefaults" xlink:type="simple" xlink:href="tmb-20241231.xsd#DisclosureStandardAndCustomAxisDomainDefaults" />
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-roles-2024.xsd#eedm" />
  <link:arcroleRef arcroleURI="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/arcrole/esma-arcrole-2018-11-21.xsd#wider-narrower" />
  <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://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:title="Extensible Enumeration Domain Members" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.fortunasilver.com/role/DisclosureStandardAndCustomAxisDomainDefaults">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressesAddressTypeAxis" xlink:label="EntityAddressesAddressTypeAxis" xlink:title="EntityAddressesAddressTypeAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AddressTypeDomain" xlink:label="AddressTypeDomain" xlink:title="AddressTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="EntityAddressesAddressTypeAxis" xlink:to="AddressTypeDomain" xlink:title="definition: EntityAddressesAddressTypeAxis to AddressTypeDomain" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentsAxis" xlink:label="SegmentsAxis" xlink:title="SegmentsAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentsDomain" xlink:label="ifrs-full_SegmentsDomain" xlink:title="SegmentsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SegmentsAxis" xlink:to="ifrs-full_SegmentsDomain" xlink:title="definition: SegmentsAxis to SegmentsMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasAxis" xlink:label="GeographicalAreasAxis" xlink:title="GeographicalAreasAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasDomain" xlink:label="ifrs-full_GeographicalAreasDomain" xlink:title="GeographicalAreasMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="GeographicalAreasAxis" xlink:to="ifrs-full_GeographicalAreasDomain" xlink:title="definition: GeographicalAreasAxis to GeographicalAreasMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityAxis" xlink:label="ComponentsOfEquityAxis" xlink:title="ComponentsOfEquityAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ifrs-full_ComponentsOfEquityDomain" xlink:title="EquityMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ComponentsOfEquityAxis" xlink:to="ifrs-full_ComponentsOfEquityDomain" xlink:title="definition: ComponentsOfEquityAxis to EquityMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:label="ClassesOfPropertyPlantAndEquipmentAxis" xlink:title="ClassesOfPropertyPlantAndEquipmentAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:title="PropertyPlantAndEquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:title="definition: ClassesOfPropertyPlantAndEquipmentAxis to PropertyPlantAndEquipmentMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfProvisionsAxis" xlink:label="ClassesOfProvisionsAxis" xlink:title="ClassesOfProvisionsAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfOtherProvisionsDomain" xlink:label="ifrs-full_ClassesOfOtherProvisionsDomain" xlink:title="OtherProvisionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfProvisionsAxis" xlink:to="ifrs-full_ClassesOfOtherProvisionsDomain" xlink:title="definition: ClassesOfProvisionsAxis to OtherProvisionsMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentConsolidationItemsAxis" xlink:label="SegmentConsolidationItemsAxis" xlink:title="SegmentConsolidationItemsAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentConsolidationItemsDomain" xlink:label="ifrs-full_SegmentConsolidationItemsDomain" xlink:title="EntitysTotalForSegmentConsolidationItemsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SegmentConsolidationItemsAxis" xlink:to="ifrs-full_SegmentConsolidationItemsDomain" xlink:title="definition: SegmentConsolidationItemsAxis to EntitysTotalForSegmentConsolidationItemsMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RetrospectiveApplicationAndRetrospectiveRestatementAxis" xlink:label="RetrospectiveApplicationAndRetrospectiveRestatementAxis" xlink:title="RetrospectiveApplicationAndRetrospectiveRestatementAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RestatedMember" xlink:label="RestatedMember" xlink:title="RestatedMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RetrospectiveApplicationAndRetrospectiveRestatementAxis" xlink:to="RestatedMember" xlink:title="definition: RetrospectiveApplicationAndRetrospectiveRestatementAxis to RestatedMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis" xlink:title="LegalEntityAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityDomain" xlink:label="EntityDomain" xlink:title="EntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" xlink:title="definition: LegalEntityAxis to EntityDomain" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameAxis" xlink:label="BorrowingsByNameAxis" xlink:title="BorrowingsByNameAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameDomain" xlink:label="ifrs-full_BorrowingsByNameDomain" xlink:title="BorrowingsByNameMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BorrowingsByNameAxis" xlink:to="ifrs-full_BorrowingsByNameDomain" xlink:title="definition: BorrowingsByNameAxis to BorrowingsByNameMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" xlink:label="TypesOfSharebasedPaymentArrangementsAxis" xlink:title="TypesOfSharebasedPaymentArrangementsAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:label="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:title="SharebasedPaymentArrangementsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypesOfSharebasedPaymentArrangementsAxis" xlink:to="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:title="definition: TypesOfSharebasedPaymentArrangementsAxis to SharebasedPaymentArrangementsMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="ifrs-full_RangeDomain" xlink:title="RangesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="ifrs-full_RangeDomain" xlink:title="definition: RangeAxis to RangesMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_VestingTrancheAxis" xlink:label="VestingTrancheAxis" xlink:title="VestingTrancheAxis" />
    <link:loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_VestingTrancheMember" xlink:label="VestingTrancheMember" xlink:title="VestingTrancheMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="VestingTrancheAxis" xlink:to="VestingTrancheMember" xlink:title="definition: VestingTrancheAxis to VestingTrancheMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CategoriesOfRelatedPartiesAxis" xlink:label="CategoriesOfRelatedPartiesAxis" xlink:title="CategoriesOfRelatedPartiesAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CategoriesOfRelatedPartiesDomain" xlink:label="ifrs-full_CategoriesOfRelatedPartiesDomain" xlink:title="EntitysTotalForRelatedPartiesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="CategoriesOfRelatedPartiesAxis" xlink:to="ifrs-full_CategoriesOfRelatedPartiesDomain" xlink:title="definition: CategoriesOfRelatedPartiesAxis to EntitysTotalForRelatedPartiesMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfRisksAxis" xlink:label="TypesOfRisksAxis" xlink:title="TypesOfRisksAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfRisksDomain" xlink:label="ifrs-full_TypesOfRisksDomain" xlink:title="TypesOfRisksMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypesOfRisksAxis" xlink:to="ifrs-full_TypesOfRisksDomain" xlink:title="definition: TypesOfRisksAxis to TypesOfRisksMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_StatementScenarioAxis" xlink:label="StatementScenarioAxis" xlink:title="StatementScenarioAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="ScenarioUnspecifiedDomain" xlink:title="ScenarioUnspecifiedDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementScenarioAxis" xlink:to="ScenarioUnspecifiedDomain" xlink:title="definition: StatementScenarioAxis to ScenarioUnspecifiedDomain" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MaturityAxis" xlink:label="MaturityAxis" xlink:title="MaturityAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MaturityDomain" xlink:label="ifrs-full_MaturityDomain" xlink:title="AggregatedTimeBandsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="MaturityAxis" xlink:to="ifrs-full_MaturityDomain" xlink:title="definition: MaturityAxis to AggregatedTimeBandsMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfFinancialAssetsAxis" xlink:label="ClassesOfFinancialAssetsAxis" xlink:title="ClassesOfFinancialAssetsAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfFinancialAssetsDomain" xlink:label="ifrs-full_ClassesOfFinancialAssetsDomain" xlink:title="FinancialAssetsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfFinancialAssetsAxis" xlink:to="ifrs-full_ClassesOfFinancialAssetsDomain" xlink:title="definition: ClassesOfFinancialAssetsAxis to FinancialAssetsMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AssetsAndLiabilitiesAxis" xlink:label="AssetsAndLiabilitiesAxis" xlink:title="AssetsAndLiabilitiesAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AssetsAndLiabilitiesDomain" xlink:label="ifrs-full_AssetsAndLiabilitiesDomain" xlink:title="AssetsAndLiabilitiesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AssetsAndLiabilitiesAxis" xlink:to="ifrs-full_AssetsAndLiabilitiesDomain" xlink:title="definition: AssetsAndLiabilitiesAxis to AssetsAndLiabilitiesMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TypeOfCommodityAxis" xlink:label="TypeOfCommodityAxis" xlink:title="TypeOfCommodityAxis" />
    <link:loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TypeOfCommodityMember" xlink:label="TypeOfCommodityMember" xlink:title="TypeOfCommodityMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypeOfCommodityAxis" xlink:to="TypeOfCommodityMember" xlink:title="definition: TypeOfCommodityAxis to TypeOfCommodityMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" xlink:label="NonadjustingEventsAfterReportingPeriodAxis" xlink:title="NonadjustingEventsAfterReportingPeriodAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" xlink:label="ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" xlink:title="NonadjustingEventsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="NonadjustingEventsAfterReportingPeriodAxis" xlink:to="ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" xlink:title="definition: NonadjustingEventsAfterReportingPeriodAxis to NonadjustingEventsMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SignificantInvestmentsInSubsidiariesAxis" xlink:label="SignificantInvestmentsInSubsidiariesAxis" xlink:title="SignificantInvestmentsInSubsidiariesAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SignificantInvestmentsInSubsidiariesDomain" xlink:label="ifrs-full_SignificantInvestmentsInSubsidiariesDomain" xlink:title="EntitysTotalForSubsidiariesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SignificantInvestmentsInSubsidiariesAxis" xlink:to="ifrs-full_SignificantInvestmentsInSubsidiariesDomain" xlink:title="definition: SignificantInvestmentsInSubsidiariesAxis to EntitysTotalForSubsidiariesMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfAssetsAxis" xlink:label="ClassesOfAssetsAxis" xlink:title="ClassesOfAssetsAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfAssetsDomain" xlink:label="ifrs-full_ClassesOfAssetsDomain" xlink:title="ClassesOfAssetsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfAssetsAxis" xlink:to="ifrs-full_ClassesOfAssetsDomain" xlink:title="definition: ClassesOfAssetsAxis to ClassesOfAssetsMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis" xlink:label="CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis" xlink:title="CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CarryingAmountMember" xlink:label="CarryingAmountMember" xlink:title="CarryingAmountMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis" xlink:to="CarryingAmountMember" xlink:title="definition: CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis to CarryingAmountMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsAxis" xlink:label="BusinessCombinationsAxis" xlink:title="BusinessCombinationsAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="ifrs-full_BusinessCombinationsDomain" xlink:title="EntitysTotalForBusinessCombinationsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessCombinationsAxis" xlink:to="ifrs-full_BusinessCombinationsDomain" xlink:title="definition: BusinessCombinationsAxis to EntitysTotalForBusinessCombinationsMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_TitleOfIndividualAxis" xlink:label="TitleOfIndividualAxis" xlink:title="TitleOfIndividualAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="TitleOfIndividualWithRelationshipToEntityDomain" xlink:title="TitleOfIndividualWithRelationshipToEntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TitleOfIndividualAxis" xlink:to="TitleOfIndividualWithRelationshipToEntityDomain" xlink:title="definition: TitleOfIndividualAxis to TitleOfIndividualWithRelationshipToEntityDomain" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesArisingFromFinancingActivitiesAxis" xlink:label="LiabilitiesArisingFromFinancingActivitiesAxis" xlink:title="LiabilitiesArisingFromFinancingActivitiesAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesArisingFromFinancingActivitiesDomain" xlink:label="ifrs-full_LiabilitiesArisingFromFinancingActivitiesDomain" xlink:title="LiabilitiesArisingFromFinancingActivitiesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LiabilitiesArisingFromFinancingActivitiesAxis" xlink:to="ifrs-full_LiabilitiesArisingFromFinancingActivitiesDomain" xlink:title="definition: LiabilitiesArisingFromFinancingActivitiesAxis to LiabilitiesArisingFromFinancingActivitiesMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfInterestRatesAxis" xlink:label="TypesOfInterestRatesAxis" xlink:title="TypesOfInterestRatesAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfInterestRatesDomain" xlink:label="ifrs-full_TypesOfInterestRatesDomain" xlink:title="InterestRateTypesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypesOfInterestRatesAxis" xlink:to="ifrs-full_TypesOfInterestRatesDomain" xlink:title="definition: TypesOfInterestRatesAxis to InterestRateTypesMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UnobservableInputsAxis" xlink:label="UnobservableInputsAxis" xlink:title="UnobservableInputsAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UnobservableInputsDomain" xlink:label="ifrs-full_UnobservableInputsDomain" xlink:title="UnobservableInputsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="UnobservableInputsAxis" xlink:to="ifrs-full_UnobservableInputsDomain" xlink:title="definition: UnobservableInputsAxis to UnobservableInputsMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ValuationTechniquesUsedInFairValueMeasurementAxis" xlink:label="ValuationTechniquesUsedInFairValueMeasurementAxis" xlink:title="ValuationTechniquesUsedInFairValueMeasurementAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ValuationTechniquesUsedInFairValueMeasurementDomain" xlink:label="ifrs-full_ValuationTechniquesUsedInFairValueMeasurementDomain" xlink:title="ValuationTechniquesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ValuationTechniquesUsedInFairValueMeasurementAxis" xlink:to="ifrs-full_ValuationTechniquesUsedInFairValueMeasurementDomain" xlink:title="definition: ValuationTechniquesUsedInFairValueMeasurementAxis to ValuationTechniquesMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfContingentLiabilitiesAxis" xlink:label="ClassesOfContingentLiabilitiesAxis" xlink:title="ClassesOfContingentLiabilitiesAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfContingentLiabilitiesDomain" xlink:label="ifrs-full_ClassesOfContingentLiabilitiesDomain" xlink:title="ContingentLiabilitiesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfContingentLiabilitiesAxis" xlink:to="ifrs-full_ClassesOfContingentLiabilitiesDomain" xlink:title="definition: ClassesOfContingentLiabilitiesAxis to ContingentLiabilitiesMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PeriodOfTaxAssessmentAxis" xlink:label="PeriodOfTaxAssessmentAxis" xlink:title="PeriodOfTaxAssessmentAxis" />
    <link:loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PeriodOfTaxAssessmentDomain" xlink:label="PeriodOfTaxAssessmentDomain" xlink:title="PeriodOfTaxAssessmentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="PeriodOfTaxAssessmentAxis" xlink:to="PeriodOfTaxAssessmentDomain" xlink:title="definition: PeriodOfTaxAssessmentAxis to PeriodOfTaxAssessmentDomain" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfShareCapitalAxis" xlink:label="ClassesOfShareCapitalAxis" xlink:title="ClassesOfShareCapitalAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfShareCapitalDomain" xlink:label="ifrs-full_ClassesOfShareCapitalDomain" xlink:title="ClassesOfShareCapitalMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfShareCapitalAxis" xlink:to="ifrs-full_ClassesOfShareCapitalDomain" xlink:title="definition: ClassesOfShareCapitalAxis to ClassesOfShareCapitalMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfOrdinarySharesAxis" xlink:label="ClassesOfOrdinarySharesAxis" xlink:title="ClassesOfOrdinarySharesAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfOrdinarySharesDomain" xlink:label="ifrs-full_ClassesOfOrdinarySharesDomain" xlink:title="OrdinarySharesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfOrdinarySharesAxis" xlink:to="ifrs-full_ClassesOfOrdinarySharesDomain" xlink:title="definition: ClassesOfOrdinarySharesAxis to OrdinarySharesMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_AntidilutiveSecuritiesAxis" xlink:label="AntidilutiveSecuritiesAxis" xlink:title="AntidilutiveSecuritiesAxis" />
    <link:loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_AntidilutiveSecuritiesMember" xlink:label="AntidilutiveSecuritiesMember" xlink:title="AntidilutiveSecuritiesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AntidilutiveSecuritiesAxis" xlink:to="AntidilutiveSecuritiesMember" xlink:title="definition: AntidilutiveSecuritiesAxis to AntidilutiveSecuritiesMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProductsAndServicesAxis" xlink:label="ProductsAndServicesAxis" xlink:title="ProductsAndServicesAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProductsAndServicesDomain" xlink:label="ifrs-full_ProductsAndServicesDomain" xlink:title="ProductsAndServicesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ProductsAndServicesAxis" xlink:to="ifrs-full_ProductsAndServicesDomain" xlink:title="definition: ProductsAndServicesAxis to ProductsAndServicesMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MajorCustomersAxis" xlink:label="MajorCustomersAxis" xlink:title="MajorCustomersAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MajorCustomersDomain" xlink:label="ifrs-full_MajorCustomersDomain" xlink:title="MajorCustomersMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="MajorCustomersAxis" xlink:to="ifrs-full_MajorCustomersDomain" xlink:title="definition: MajorCustomersAxis to MajorCustomersMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" xlink:label="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" xlink:title="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:label="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:title="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" xlink:to="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:title="definition: TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis to TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MeasurementAxis" xlink:label="MeasurementAxis" xlink:title="MeasurementAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MeasurementDomain" xlink:label="ifrs-full_MeasurementDomain" xlink:title="AggregatedMeasurementMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="MeasurementAxis" xlink:to="ifrs-full_MeasurementDomain" xlink:title="definition: MeasurementAxis to AggregatedMeasurementMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfLiabilitiesAxis" xlink:label="ClassesOfLiabilitiesAxis" xlink:title="ClassesOfLiabilitiesAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfLiabilitiesDomain" xlink:label="ifrs-full_ClassesOfLiabilitiesDomain" xlink:title="LiabilitiesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfLiabilitiesAxis" xlink:to="ifrs-full_ClassesOfLiabilitiesDomain" xlink:title="definition: ClassesOfLiabilitiesAxis to LiabilitiesMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LevelsOfFairValueHierarchyAxis" xlink:label="LevelsOfFairValueHierarchyAxis" xlink:title="LevelsOfFairValueHierarchyAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LevelsOfFairValueHierarchyDomain" xlink:label="ifrs-full_LevelsOfFairValueHierarchyDomain" xlink:title="AllLevelsOfFairValueHierarchyMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LevelsOfFairValueHierarchyAxis" xlink:to="ifrs-full_LevelsOfFairValueHierarchyDomain" xlink:title="definition: LevelsOfFairValueHierarchyAxis to AllLevelsOfFairValueHierarchyMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CategoriesOfFinancialAssetsAxis" xlink:label="CategoriesOfFinancialAssetsAxis" xlink:title="CategoriesOfFinancialAssetsAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CategoriesOfFinancialAssetsDomain" xlink:label="ifrs-full_CategoriesOfFinancialAssetsDomain" xlink:title="FinancialAssetsCategoryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="CategoriesOfFinancialAssetsAxis" xlink:to="ifrs-full_CategoriesOfFinancialAssetsDomain" xlink:title="definition: CategoriesOfFinancialAssetsAxis to FinancialAssetsCategoryMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CategoriesOfFinancialLiabilitiesAxis" xlink:label="CategoriesOfFinancialLiabilitiesAxis" xlink:title="CategoriesOfFinancialLiabilitiesAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CategoriesOfFinancialLiabilitiesDomain" xlink:label="ifrs-full_CategoriesOfFinancialLiabilitiesDomain" xlink:title="FinancialLiabilitiesCategoryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="CategoriesOfFinancialLiabilitiesAxis" xlink:to="ifrs-full_CategoriesOfFinancialLiabilitiesDomain" xlink:title="definition: CategoriesOfFinancialLiabilitiesAxis to FinancialLiabilitiesCategoryMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfHedgesAxis" xlink:label="TypesOfHedgesAxis" xlink:title="TypesOfHedgesAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfHedgesDomain" xlink:label="ifrs-full_TypesOfHedgesDomain" xlink:title="TypesOfHedgesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypesOfHedgesAxis" xlink:to="ifrs-full_TypesOfHedgesDomain" xlink:title="definition: TypesOfHedgesAxis to TypesOfHedgesMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_InitiallyAppliedIFRSsAxis" xlink:label="InitiallyAppliedIFRSsAxis" xlink:title="InitiallyAppliedIFRSsAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_InitiallyAppliedIFRSsDomain" xlink:label="ifrs-full_InitiallyAppliedIFRSsDomain" xlink:title="InitiallyAppliedIFRSsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="InitiallyAppliedIFRSsAxis" xlink:to="ifrs-full_InitiallyAppliedIFRSsDomain" xlink:title="definition: InitiallyAppliedIFRSsAxis to InitiallyAppliedIFRSsMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SignificantInvestmentsInAssociatesAxis" xlink:label="SignificantInvestmentsInAssociatesAxis" xlink:title="SignificantInvestmentsInAssociatesAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SignificantInvestmentsInAssociatesDomain" xlink:label="ifrs-full_SignificantInvestmentsInAssociatesDomain" xlink:title="EntitysTotalForAssociatesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SignificantInvestmentsInAssociatesAxis" xlink:to="ifrs-full_SignificantInvestmentsInAssociatesDomain" xlink:title="definition: SignificantInvestmentsInAssociatesAxis to EntitysTotalForAssociatesMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DerivativeContractEnteredPeriodAxis" xlink:label="DerivativeContractEnteredPeriodAxis" xlink:title="DerivativeContractEnteredPeriodAxis" />
    <link:loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DerivativeContractEnteredPeriodMember" xlink:label="DerivativeContractEnteredPeriodMember" xlink:title="DerivativeContractEnteredPeriodMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DerivativeContractEnteredPeriodAxis" xlink:to="DerivativeContractEnteredPeriodMember" xlink:title="definition: DerivativeContractEnteredPeriodAxis to DerivativeContractEnteredPeriodMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IndividualAssetsOrCashgeneratingUnitsAxis" xlink:label="IndividualAssetsOrCashgeneratingUnitsAxis" xlink:title="IndividualAssetsOrCashgeneratingUnitsAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IndividualAssetsOrCashgeneratingUnitsDomain" xlink:label="ifrs-full_IndividualAssetsOrCashgeneratingUnitsDomain" xlink:title="EntitysTotalForIndividualAssetsOrCashgeneratingUnitsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="IndividualAssetsOrCashgeneratingUnitsAxis" xlink:to="ifrs-full_IndividualAssetsOrCashgeneratingUnitsDomain" xlink:title="definition: IndividualAssetsOrCashgeneratingUnitsAxis to EntitysTotalForIndividualAssetsOrCashgeneratingUnitsMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CurrencyAxis" xlink:label="CurrencyAxis" xlink:title="CurrencyAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2024/currency-2024.xsd#currency_AllCurrenciesDomain" xlink:label="AllCurrenciesDomain" xlink:title="AllCurrenciesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="CurrencyAxis" xlink:to="AllCurrenciesDomain" xlink:title="definition: CurrencyAxis to AllCurrenciesDomain" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsAssetAcquisitionsAxis" xlink:label="IfrsAssetAcquisitionsAxis" xlink:title="IfrsAssetAcquisitionsAxis" />
    <link:loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsAssetAcquisitionsDomain" xlink:label="IfrsAssetAcquisitionsDomain" xlink:title="IfrsAssetAcquisitionsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="IfrsAssetAcquisitionsAxis" xlink:to="IfrsAssetAcquisitionsDomain" xlink:title="definition: IfrsAssetAcquisitionsAxis to IfrsAssetAcquisitionsDomain" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AttributionOfExpensesByNatureToTheirFunctionAxis" xlink:label="AttributionOfExpensesByNatureToTheirFunctionAxis" xlink:title="AttributionOfExpensesByNatureToTheirFunctionAxis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AttributionOfExpensesByNatureToTheirFunctionDomain" xlink:label="ifrs-full_AttributionOfExpensesByNatureToTheirFunctionDomain" xlink:title="LineItemsByFunctionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AttributionOfExpensesByNatureToTheirFunctionAxis" xlink:to="ifrs-full_AttributionOfExpensesByNatureToTheirFunctionDomain" xlink:title="definition: AttributionOfExpensesByNatureToTheirFunctionAxis to LineItemsByFunctionMember" use="optional" order="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfFinancialLiabilitiesAxis" xlink:label="ifrs-full_ClassesOfFinancialLiabilitiesAxis_1" xlink:title="ifrs-full_ClassesOfFinancialLiabilitiesAxis_1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfFinancialLiabilitiesDomain" xlink:label="ifrs-full_ClassesOfFinancialLiabilitiesDomain_1" xlink:title="ifrs-full_FinancialLiabilitiesMember_1" />
    <link:definitionArc xlink:type="arc" xlink:from="ifrs-full_ClassesOfFinancialLiabilitiesAxis_1" xlink:to="ifrs-full_ClassesOfFinancialLiabilitiesDomain_1" use="optional" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:title="definition:ifrs-full_ClassesOfFinancialLiabilitiesAxis_1 To ifrs-full_FinancialLiabilitiesMember_1" order="1" />
  </link:definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DocumentDocumentAndEntityInformation" xlink:type="extended" xlink:title="00090 - Document - Document And Entity Information" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentInformationTable" xlink:label="dei_DocumentInformationTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressesAddressTypeAxis" xlink:label="dei_EntityAddressesAddressTypeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="dei_DocumentInformationTable" xlink:to="dei_EntityAddressesAddressTypeAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AddressTypeDomain" xlink:label="dei_AddressTypeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="dei_EntityAddressesAddressTypeAxis" xlink:to="dei_AddressTypeDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_BusinessContactMember" xlink:label="dei_BusinessContactMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="dei_AddressTypeDomain" xlink:to="dei_BusinessContactMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentInformationLineItems" xlink:label="dei_DocumentInformationLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_DocumentInformationTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityRegistrantName" xlink:label="dei_EntityRegistrantName" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityRegistrantName" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityCentralIndexKey" xlink:label="dei_EntityCentralIndexKey" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityCentralIndexKey" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentType" xlink:label="dei_DocumentType" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_DocumentType" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentRegistrationStatement" xlink:label="dei_DocumentRegistrationStatement" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_DocumentRegistrationStatement" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentAnnualReport" xlink:label="dei_DocumentAnnualReport" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_DocumentAnnualReport" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AmendmentFlag" xlink:label="dei_AmendmentFlag" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_AmendmentFlag" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentPeriodEndDate" xlink:label="dei_DocumentPeriodEndDate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_DocumentPeriodEndDate" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityFileNumber" xlink:label="dei_EntityFileNumber" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityFileNumber" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityIncorporationStateCountryCode" xlink:label="dei_EntityIncorporationStateCountryCode" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityIncorporationStateCountryCode" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityPrimarySicNumber" xlink:label="dei_EntityPrimarySicNumber" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityPrimarySicNumber" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityTaxIdentificationNumber" xlink:label="dei_EntityTaxIdentificationNumber" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="12" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityTaxIdentificationNumber" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressAddressLine1" xlink:label="dei_EntityAddressAddressLine1" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="13" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityAddressAddressLine1" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressAddressLine2" xlink:label="dei_EntityAddressAddressLine2" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="14" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityAddressAddressLine2" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressCityOrTown" xlink:label="dei_EntityAddressCityOrTown" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="15" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityAddressCityOrTown" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressStateOrProvince" xlink:label="dei_EntityAddressStateOrProvince" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="16" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityAddressStateOrProvince" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressPostalZipCode" xlink:label="dei_EntityAddressPostalZipCode" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="17" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityAddressPostalZipCode" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressCountry" xlink:label="dei_EntityAddressCountry" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="18" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityAddressCountry" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_CityAreaCode" xlink:label="dei_CityAreaCode" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="19" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_CityAreaCode" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_LocalPhoneNumber" xlink:label="dei_LocalPhoneNumber" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="20" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_LocalPhoneNumber" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_ContactPersonnelName" xlink:label="dei_ContactPersonnelName" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="21" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_ContactPersonnelName" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_Security12bTitle" xlink:label="dei_Security12bTitle" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="22" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_Security12bTitle" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_TradingSymbol" xlink:label="dei_TradingSymbol" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="23" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_TradingSymbol" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_SecurityExchangeName" xlink:label="dei_SecurityExchangeName" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="24" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_SecurityExchangeName" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AnnualInformationForm" xlink:label="dei_AnnualInformationForm" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="25" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_AnnualInformationForm" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AuditedAnnualFinancialStatements" xlink:label="dei_AuditedAnnualFinancialStatements" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="26" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_AuditedAnnualFinancialStatements" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentFiscalPeriodFocus" xlink:label="dei_DocumentFiscalPeriodFocus" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="27" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_DocumentFiscalPeriodFocus" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentFiscalYearFocus" xlink:label="dei_DocumentFiscalYearFocus" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="28" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_DocumentFiscalYearFocus" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_CurrentFiscalYearEndDate" xlink:label="dei_CurrentFiscalYearEndDate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="29" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_CurrentFiscalYearEndDate" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityInteractiveDataCurrent" xlink:label="dei_EntityInteractiveDataCurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="30" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityInteractiveDataCurrent" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityCurrentReportingStatus" xlink:label="dei_EntityCurrentReportingStatus" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="31" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityCurrentReportingStatus" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityEmergingGrowthCompany" xlink:label="dei_EntityEmergingGrowthCompany" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="32" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityEmergingGrowthCompany" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_IcfrAuditorAttestationFlag" xlink:label="dei_IcfrAuditorAttestationFlag" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="33" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_IcfrAuditorAttestationFlag" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityCommonStockSharesOutstanding" xlink:label="dei_EntityCommonStockSharesOutstanding" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="34" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityCommonStockSharesOutstanding" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AuditorName" xlink:label="dei_AuditorName" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="35" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_AuditorName" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AuditorFirmId" xlink:label="dei_AuditorFirmId" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="36" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_AuditorFirmId" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AuditorLocation" xlink:label="dei_AuditorLocation" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="37" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_AuditorLocation" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentFinStmtErrorCorrectionFlag" xlink:label="dei_DocumentFinStmtErrorCorrectionFlag" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="38" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_DocumentFinStmtErrorCorrectionFlag" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/StatementConsolidatedStatementsOfCashFlows" xlink:type="extended" xlink:title="00400 - Statement - Consolidated Statements of Cash Flows" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOperatingSegmentsTable" xlink:label="ifrs-full_DisclosureOfOperatingSegmentsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameAxis" xlink:label="ifrs-full_BorrowingsByNameAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsTable" xlink:to="ifrs-full_BorrowingsByNameAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameDomain" xlink:label="ifrs-full_BorrowingsByNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_BorrowingsByNameAxis" xlink:to="ifrs-full_BorrowingsByNameDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TermCreditFacilityMember" xlink:label="fsm_TermCreditFacilityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_BorrowingsByNameDomain" xlink:to="fsm_TermCreditFacilityMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebenturesMember" xlink:label="fsm_DebenturesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_BorrowingsByNameDomain" xlink:to="fsm_DebenturesMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ConvertibleNotes2024Member" xlink:label="fsm_ConvertibleNotes2024Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_BorrowingsByNameDomain" xlink:to="fsm_ConvertibleNotes2024Member" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:label="ifrs-full_DisclosureOfOperatingSegmentsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_DisclosureOfOperatingSegmentsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashFlowsFromUsedInOperatingActivitiesAbstract" xlink:label="ifrs-full_CashFlowsFromUsedInOperatingActivitiesAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_CashFlowsFromUsedInOperatingActivitiesAbstract" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProfitLoss" xlink:label="ifrs-full_ProfitLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_CashFlowsFromUsedInOperatingActivitiesAbstract" xlink:to="ifrs-full_ProfitLoss" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AdjustmentsForReconcileProfitLossAbstract" xlink:label="ifrs-full_AdjustmentsForReconcileProfitLossAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_CashFlowsFromUsedInOperatingActivitiesAbstract" xlink:to="ifrs-full_AdjustmentsForReconcileProfitLossAbstract" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AdjustmentsForDepreciationAndAmortisationExpense" xlink:label="ifrs-full_AdjustmentsForDepreciationAndAmortisationExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_AdjustmentsForReconcileProfitLossAbstract" xlink:to="ifrs-full_AdjustmentsForDepreciationAndAmortisationExpense" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_AccretionOfProvisionRelatedToOperatingActivities" xlink:label="fsm_AccretionOfProvisionRelatedToOperatingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_AdjustmentsForReconcileProfitLossAbstract" xlink:to="fsm_AccretionOfProvisionRelatedToOperatingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AdjustmentsForIncomeTaxExpense" xlink:label="ifrs-full_AdjustmentsForIncomeTaxExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_AdjustmentsForReconcileProfitLossAbstract" xlink:to="ifrs-full_AdjustmentsForIncomeTaxExpense" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_InterestExpenseOperatingActivities" xlink:label="fsm_InterestExpenseOperatingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_AdjustmentsForReconcileProfitLossAbstract" xlink:to="fsm_InterestExpenseOperatingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_AdjustmentsForSharebasedPaymentsExpenseAndRecoveryNetOfCashSettlements" xlink:label="fsm_AdjustmentsForSharebasedPaymentsExpenseAndRecoveryNetOfCashSettlements" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_AdjustmentsForReconcileProfitLossAbstract" xlink:to="fsm_AdjustmentsForSharebasedPaymentsExpenseAndRecoveryNetOfCashSettlements" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AdjustmentsForImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss" xlink:label="ifrs-full_AdjustmentsForImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_AdjustmentsForReconcileProfitLossAbstract" xlink:to="ifrs-full_AdjustmentsForImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_InventoryWritedown2011" xlink:label="ifrs-full_InventoryWritedown2011" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_AdjustmentsForReconcileProfitLossAbstract" xlink:to="ifrs-full_InventoryWritedown2011" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ProvisionForInventory" xlink:label="fsm_ProvisionForInventory" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_AdjustmentsForReconcileProfitLossAbstract" xlink:to="fsm_ProvisionForInventory" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ImpairmentLossRecognisedInProfitOrLossPropertyPlantAndEquipment" xlink:label="ifrs-full_ImpairmentLossRecognisedInProfitOrLossPropertyPlantAndEquipment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_AdjustmentsForReconcileProfitLossAbstract" xlink:to="ifrs-full_ImpairmentLossRecognisedInProfitOrLossPropertyPlantAndEquipment" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AdjustmentsForUnrealisedForeignExchangeLossesGains" xlink:label="ifrs-full_AdjustmentsForUnrealisedForeignExchangeLossesGains" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="ifrs-full_AdjustmentsForReconcileProfitLossAbstract" xlink:to="ifrs-full_AdjustmentsForUnrealisedForeignExchangeLossesGains" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_OtherInvestmentIncomeExpense" xlink:label="fsm_OtherInvestmentIncomeExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="ifrs-full_AdjustmentsForReconcileProfitLossAbstract" xlink:to="fsm_OtherInvestmentIncomeExpense" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherAdjustmentsToReconcileProfitLoss" xlink:label="ifrs-full_OtherAdjustmentsToReconcileProfitLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="12" xlink:from="ifrs-full_AdjustmentsForReconcileProfitLossAbstract" xlink:to="ifrs-full_OtherAdjustmentsToReconcileProfitLoss" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PaymentOnClosureAndRehabilitationProvisions" xlink:label="fsm_PaymentOnClosureAndRehabilitationProvisions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="13" xlink:from="ifrs-full_AdjustmentsForReconcileProfitLossAbstract" xlink:to="fsm_PaymentOnClosureAndRehabilitationProvisions" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseInWorkingCapital" xlink:label="ifrs-full_IncreaseDecreaseInWorkingCapital" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_CashFlowsFromUsedInOperatingActivitiesAbstract" xlink:to="ifrs-full_IncreaseDecreaseInWorkingCapital" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashFlowsFromUsedInOperations" xlink:label="ifrs-full_CashFlowsFromUsedInOperations" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_CashFlowsFromUsedInOperatingActivitiesAbstract" xlink:to="ifrs-full_CashFlowsFromUsedInOperations" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncomeTaxesPaidClassifiedAsOperatingActivities" xlink:label="ifrs-full_IncomeTaxesPaidClassifiedAsOperatingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_CashFlowsFromUsedInOperatingActivitiesAbstract" xlink:to="ifrs-full_IncomeTaxesPaidClassifiedAsOperatingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_InterestPaidClassifiedAsOperatingActivities" xlink:label="ifrs-full_InterestPaidClassifiedAsOperatingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_CashFlowsFromUsedInOperatingActivitiesAbstract" xlink:to="ifrs-full_InterestPaidClassifiedAsOperatingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_InterestReceivedClassifiedAsOperatingActivities" xlink:label="ifrs-full_InterestReceivedClassifiedAsOperatingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_CashFlowsFromUsedInOperatingActivitiesAbstract" xlink:to="ifrs-full_InterestReceivedClassifiedAsOperatingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashFlowsFromUsedInOperatingActivities" xlink:label="ifrs-full_CashFlowsFromUsedInOperatingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_CashFlowsFromUsedInOperatingActivitiesAbstract" xlink:to="ifrs-full_CashFlowsFromUsedInOperatingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashFlowsFromUsedInInvestingActivitiesAbstract" xlink:label="ifrs-full_CashFlowsFromUsedInInvestingActivitiesAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_CashFlowsFromUsedInInvestingActivitiesAbstract" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PurchaseOfMiningAssets" xlink:label="ifrs-full_PurchaseOfMiningAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_CashFlowsFromUsedInInvestingActivitiesAbstract" xlink:to="ifrs-full_PurchaseOfMiningAssets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PurchaseOfAvailableForSaleSecurities" xlink:label="fsm_PurchaseOfAvailableForSaleSecurities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_CashFlowsFromUsedInInvestingActivitiesAbstract" xlink:to="fsm_PurchaseOfAvailableForSaleSecurities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ProceedsFromAvailableForSaleFinancialAssets" xlink:label="fsm_ProceedsFromAvailableForSaleFinancialAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_CashFlowsFromUsedInInvestingActivitiesAbstract" xlink:to="fsm_ProceedsFromAvailableForSaleFinancialAssets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CashFlowsInvestingActivitiesDepositsOnLongTermAssets" xlink:label="fsm_CashFlowsInvestingActivitiesDepositsOnLongTermAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_CashFlowsFromUsedInInvestingActivitiesAbstract" xlink:to="fsm_CashFlowsInvestingActivitiesDepositsOnLongTermAssets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashFlowsUsedInObtainingControlOfSubsidiariesOrOtherBusinessesClassifiedAsInvestingActivities" xlink:label="ifrs-full_CashFlowsUsedInObtainingControlOfSubsidiariesOrOtherBusinessesClassifiedAsInvestingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_CashFlowsFromUsedInInvestingActivitiesAbstract" xlink:to="ifrs-full_CashFlowsUsedInObtainingControlOfSubsidiariesOrOtherBusinessesClassifiedAsInvestingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherInflowsOutflowsOfCashClassifiedAsInvestingActivities" xlink:label="ifrs-full_OtherInflowsOutflowsOfCashClassifiedAsInvestingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_CashFlowsFromUsedInInvestingActivitiesAbstract" xlink:to="ifrs-full_OtherInflowsOutflowsOfCashClassifiedAsInvestingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashFlowsFromUsedInInvestingActivities" xlink:label="ifrs-full_CashFlowsFromUsedInInvestingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_CashFlowsFromUsedInInvestingActivitiesAbstract" xlink:to="ifrs-full_CashFlowsFromUsedInInvestingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashFlowsFromUsedInFinancingActivitiesAbstract" xlink:label="ifrs-full_CashFlowsFromUsedInFinancingActivitiesAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_CashFlowsFromUsedInFinancingActivitiesAbstract" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProceedsFromBorrowingsClassifiedAsFinancingActivities" xlink:label="ifrs-full_ProceedsFromBorrowingsClassifiedAsFinancingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_CashFlowsFromUsedInFinancingActivitiesAbstract" xlink:to="ifrs-full_ProceedsFromBorrowingsClassifiedAsFinancingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RepaymentsOfBorrowingsClassifiedAsFinancingActivities" xlink:label="ifrs-full_RepaymentsOfBorrowingsClassifiedAsFinancingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_CashFlowsFromUsedInFinancingActivitiesAbstract" xlink:to="ifrs-full_RepaymentsOfBorrowingsClassifiedAsFinancingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PaymentsForDebtIssueCosts" xlink:label="ifrs-full_PaymentsForDebtIssueCosts" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_CashFlowsFromUsedInFinancingActivitiesAbstract" xlink:to="ifrs-full_PaymentsForDebtIssueCosts" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PaymentsToAcquireOrRedeemEntitysShares" xlink:label="ifrs-full_PaymentsToAcquireOrRedeemEntitysShares" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_CashFlowsFromUsedInFinancingActivitiesAbstract" xlink:to="ifrs-full_PaymentsToAcquireOrRedeemEntitysShares" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProceedsFromExerciseOfOptions" xlink:label="ifrs-full_ProceedsFromExerciseOfOptions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_CashFlowsFromUsedInFinancingActivitiesAbstract" xlink:to="ifrs-full_ProceedsFromExerciseOfOptions" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PaymentsOfLeaseLiabilitiesClassifiedAsFinancingActivities" xlink:label="ifrs-full_PaymentsOfLeaseLiabilitiesClassifiedAsFinancingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_CashFlowsFromUsedInFinancingActivitiesAbstract" xlink:to="ifrs-full_PaymentsOfLeaseLiabilitiesClassifiedAsFinancingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DividendsPaidToNoncontrollingInterestsClassifiedAsFinancingActivities" xlink:label="ifrs-full_DividendsPaidToNoncontrollingInterestsClassifiedAsFinancingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_CashFlowsFromUsedInFinancingActivitiesAbstract" xlink:to="ifrs-full_DividendsPaidToNoncontrollingInterestsClassifiedAsFinancingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashFlowsFromUsedInFinancingActivities" xlink:label="ifrs-full_CashFlowsFromUsedInFinancingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_CashFlowsFromUsedInFinancingActivitiesAbstract" xlink:to="ifrs-full_CashFlowsFromUsedInFinancingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_EffectOfExchangeRateChangesOnCashAndCashEquivalents" xlink:label="ifrs-full_EffectOfExchangeRateChangesOnCashAndCashEquivalents" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_EffectOfExchangeRateChangesOnCashAndCashEquivalents" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseInCashAndCashEquivalents" xlink:label="ifrs-full_IncreaseDecreaseInCashAndCashEquivalents" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_IncreaseDecreaseInCashAndCashEquivalents" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashAndCashEquivalents" xlink:label="ifrs-full_CashAndCashEquivalents" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_CashAndCashEquivalents" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/StatementConsolidatedStatementsOfChangesInEquity" xlink:type="extended" xlink:title="00500 - Statement - Consolidated Statements of Changes in Equity" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_StatementOfChangesInEquityTable" xlink:label="ifrs-full_StatementOfChangesInEquityTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityAxis" xlink:label="ifrs-full_ComponentsOfEquityAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_StatementOfChangesInEquityTable" xlink:to="ifrs-full_ComponentsOfEquityAxis" priority="2" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ifrs-full_ComponentsOfEquityDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ComponentsOfEquityAxis" xlink:to="ifrs-full_ComponentsOfEquityDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_EquityAttributableToOwnersOfParentMember" xlink:label="ifrs-full_EquityAttributableToOwnersOfParentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ComponentsOfEquityDomain" xlink:to="ifrs-full_EquityAttributableToOwnersOfParentMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IssuedCapitalMember" xlink:label="ifrs-full_IssuedCapitalMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_EquityAttributableToOwnersOfParentMember" xlink:to="ifrs-full_IssuedCapitalMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherReservesMember" xlink:label="ifrs-full_OtherReservesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_EquityAttributableToOwnersOfParentMember" xlink:to="ifrs-full_OtherReservesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RevaluationSurplusMember" xlink:label="ifrs-full_RevaluationSurplusMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_OtherReservesMember" xlink:to="ifrs-full_RevaluationSurplusMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ReserveOfCashFlowHedgesMember" xlink:label="ifrs-full_ReserveOfCashFlowHedgesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_OtherReservesMember" xlink:to="ifrs-full_ReserveOfCashFlowHedgesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ReserveOfGainsAndLossesOnRemeasuringAvailableForSaleSecuritiesMember" xlink:label="fsm_ReserveOfGainsAndLossesOnRemeasuringAvailableForSaleSecuritiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_OtherReservesMember" xlink:to="fsm_ReserveOfGainsAndLossesOnRemeasuringAvailableForSaleSecuritiesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ReserveOfConvertibleDebenturesMember" xlink:label="fsm_ReserveOfConvertibleDebenturesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_OtherReservesMember" xlink:to="fsm_ReserveOfConvertibleDebenturesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ReserveOfChangeInValueOfForeignCurrencyBasisSpreadsMember" xlink:label="ifrs-full_ReserveOfChangeInValueOfForeignCurrencyBasisSpreadsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_OtherReservesMember" xlink:to="ifrs-full_ReserveOfChangeInValueOfForeignCurrencyBasisSpreadsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RetainedEarningsMember" xlink:label="ifrs-full_RetainedEarningsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_EquityAttributableToOwnersOfParentMember" xlink:to="ifrs-full_RetainedEarningsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncontrollingInterestsMember" xlink:label="ifrs-full_NoncontrollingInterestsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_ComponentsOfEquityDomain" xlink:to="ifrs-full_NoncontrollingInterestsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_StatementOfChangesInEquityLineItems" xlink:label="ifrs-full_StatementOfChangesInEquityLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_StatementOfChangesInEquityTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Equity" xlink:label="ifrs-full_Equity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_Equity" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfSharesIssued" xlink:label="ifrs-full_NumberOfSharesIssued" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_NumberOfSharesIssued" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProfitLoss" xlink:label="ifrs-full_ProfitLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_ProfitLoss" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherComprehensiveIncome" xlink:label="ifrs-full_OtherComprehensiveIncome" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_OtherComprehensiveIncome" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComprehensiveIncome" xlink:label="ifrs-full_ComprehensiveIncome" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_ComprehensiveIncome" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ComprehensiveIncomeIncludingBeginningBalanceForPeriod" xlink:label="fsm_ComprehensiveIncomeIncludingBeginningBalanceForPeriod" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="fsm_ComprehensiveIncomeIncludingBeginningBalanceForPeriod" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsStockIssuedDuringPeriodSharesConversionOfConvertibleSecurities" xlink:label="fsm_IfrsStockIssuedDuringPeriodSharesConversionOfConvertibleSecurities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="fsm_IfrsStockIssuedDuringPeriodSharesConversionOfConvertibleSecurities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughAcquisitionOfSubsidiary" xlink:label="ifrs-full_IncreaseDecreaseThroughAcquisitionOfSubsidiary" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_IncreaseDecreaseThroughAcquisitionOfSubsidiary" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsStockIssuedDuringPeriodSharesAcquisitions" xlink:label="fsm_IfrsStockIssuedDuringPeriodSharesAcquisitions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="fsm_IfrsStockIssuedDuringPeriodSharesAcquisitions" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DividendsRecognisedAsDistributionsToNoncontrollingInterests" xlink:label="ifrs-full_DividendsRecognisedAsDistributionsToNoncontrollingInterests" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_DividendsRecognisedAsDistributionsToNoncontrollingInterests" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughExerciseOfOptions" xlink:label="ifrs-full_IncreaseDecreaseThroughExerciseOfOptions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="12" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_IncreaseDecreaseThroughExerciseOfOptions" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfShareOptionsExercisedInSharebasedPaymentArrangement" xlink:label="ifrs-full_NumberOfShareOptionsExercisedInSharebasedPaymentArrangement" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="13" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_NumberOfShareOptionsExercisedInSharebasedPaymentArrangement" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughConversionOfConvertibleInstruments" xlink:label="ifrs-full_IncreaseDecreaseThroughConversionOfConvertibleInstruments" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="14" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_IncreaseDecreaseThroughConversionOfConvertibleInstruments" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsStockRepurchasedAndRetiredDuringPeriodShares" xlink:label="fsm_IfrsStockRepurchasedAndRetiredDuringPeriodShares" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="15" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="fsm_IfrsStockRepurchasedAndRetiredDuringPeriodShares" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsStockRepurchasedAndRetiredDuringPeriodValue" xlink:label="fsm_IfrsStockRepurchasedAndRetiredDuringPeriodValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="16" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="fsm_IfrsStockRepurchasedAndRetiredDuringPeriodValue" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IssueOfConvertibleInstruments" xlink:label="ifrs-full_IssueOfConvertibleInstruments" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="17" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_IssueOfConvertibleInstruments" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_NumberOfSharesIssuedForConversion" xlink:label="fsm_NumberOfSharesIssuedForConversion" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="18" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="fsm_NumberOfSharesIssuedForConversion" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughSharebasedPaymentTransactions" xlink:label="ifrs-full_IncreaseDecreaseThroughSharebasedPaymentTransactions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="19" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_IncreaseDecreaseThroughSharebasedPaymentTransactions" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncreaseDecreaseThroughConvertibleDebentures" xlink:label="fsm_IncreaseDecreaseThroughConvertibleDebentures" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="20" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="fsm_IncreaseDecreaseThroughConvertibleDebentures" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TransactionWithOwnersRelatedToEquity" xlink:label="fsm_TransactionWithOwnersRelatedToEquity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="21" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="fsm_TransactionWithOwnersRelatedToEquity" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TransactionWithOwnersRelatedToEquityShares" xlink:label="fsm_TransactionWithOwnersRelatedToEquityShares" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="22" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="fsm_TransactionWithOwnersRelatedToEquityShares" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureShareBasedPaymentsTables" xlink:type="extended" xlink:title="31603 - Disclosure - SHARE-BASED PAYMENTS (Tables)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:label="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" xlink:label="ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:to="ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:label="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" xlink:to="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DeferredShareUnitsMember" xlink:label="fsm_DeferredShareUnitsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:to="fsm_DeferredShareUnitsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RestrictedShareUnitsMember" xlink:label="ifrs-full_RestrictedShareUnitsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:to="ifrs-full_RestrictedShareUnitsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PerformanceShareUnitsMember" xlink:label="fsm_PerformanceShareUnitsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:to="fsm_PerformanceShareUnitsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:label="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisclosureOfNumberAndFairValueOfOtherEquityInstrumentsExplanatoryTextBlock" xlink:label="fsm_DisclosureOfNumberAndFairValueOfOtherEquityInstrumentsExplanatoryTextBlock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="fsm_DisclosureOfNumberAndFairValueOfOtherEquityInstrumentsExplanatoryTextBlock" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNumberAndWeightedAverageExercisePricesOfShareOptionsExplanatory" xlink:label="ifrs-full_DisclosureOfNumberAndWeightedAverageExercisePricesOfShareOptionsExplanatory" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ifrs-full_DisclosureOfNumberAndWeightedAverageExercisePricesOfShareOptionsExplanatory" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureManagementOfFinancialRiskTables" xlink:type="extended" xlink:title="32703 - Disclosure - MANAGEMENT OF FINANCIAL RISK (Tables)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:label="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfRisksAxis" xlink:label="ifrs-full_TypesOfRisksAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:to="ifrs-full_TypesOfRisksAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfRisksDomain" xlink:label="ifrs-full_TypesOfRisksDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_TypesOfRisksAxis" xlink:to="ifrs-full_TypesOfRisksDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialRiskMember" xlink:label="ifrs-full_FinancialRiskMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_TypesOfRisksDomain" xlink:to="ifrs-full_FinancialRiskMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MarketRiskMember" xlink:label="ifrs-full_MarketRiskMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_FinancialRiskMember" xlink:to="ifrs-full_MarketRiskMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrencyRiskMember" xlink:label="ifrs-full_CurrencyRiskMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MarketRiskMember" xlink:to="ifrs-full_CurrencyRiskMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherPriceRiskMember" xlink:label="ifrs-full_OtherPriceRiskMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_MarketRiskMember" xlink:to="ifrs-full_OtherPriceRiskMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CommodityPriceRiskMember" xlink:label="ifrs-full_CommodityPriceRiskMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_OtherPriceRiskMember" xlink:to="ifrs-full_CommodityPriceRiskMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:label="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfCreditRiskExplanatory" xlink:label="ifrs-full_DisclosureOfCreditRiskExplanatory" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_DisclosureOfCreditRiskExplanatory" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DescriptionOfManagingLiquidityRisk" xlink:label="ifrs-full_DescriptionOfManagingLiquidityRisk" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_DescriptionOfManagingLiquidityRisk" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsExplanatory" xlink:label="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsExplanatory" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsExplanatory" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisclosureOfNatureAndExtentOfRisksArisingFromForeignExchangeCurrencyRisk" xlink:label="fsm_DisclosureOfNatureAndExtentOfRisksArisingFromForeignExchangeCurrencyRisk" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="fsm_DisclosureOfNatureAndExtentOfRisksArisingFromForeignExchangeCurrencyRisk" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisclosureOfCapitalStructureTextBlock" xlink:label="fsm_DisclosureOfCapitalStructureTextBlock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="fsm_DisclosureOfCapitalStructureTextBlock" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureNatureOfOperationsDetails" xlink:type="extended" xlink:title="40101 - Disclosure - NATURE OF OPERATIONS (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:label="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" xlink:label="ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:to="ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" xlink:label="ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" xlink:to="ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisposalOfMajorSubsidiaryMember" xlink:label="ifrs-full_DisposalOfMajorSubsidiaryMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" xlink:to="ifrs-full_DisposalOfMajorSubsidiaryMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:label="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NameOfReportingEntityOrOtherMeansOfIdentification" xlink:label="ifrs-full_NameOfReportingEntityOrOtherMeansOfIdentification" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="ifrs-full_NameOfReportingEntityOrOtherMeansOfIdentification" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DomicileOfEntity" xlink:label="ifrs-full_DomicileOfEntity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="ifrs-full_DomicileOfEntity" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PercentageOfInterestDisposed" xlink:label="fsm_PercentageOfInterestDisposed" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="fsm_PercentageOfInterestDisposed" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DescriptionOfNatureOfEntitysOperationsAndPrincipalActivities" xlink:label="ifrs-full_DescriptionOfNatureOfEntitysOperationsAndPrincipalActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="ifrs-full_DescriptionOfNatureOfEntitysOperationsAndPrincipalActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AddressOfRegisteredOfficeOfEntity" xlink:label="ifrs-full_AddressOfRegisteredOfficeOfEntity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="ifrs-full_AddressOfRegisteredOfficeOfEntity" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureMaterialAccountingPoliciesNarrativeDetails" xlink:type="extended" xlink:title="40301 - Disclosure - MATERIAL ACCOUNTING POLICIES (Narrative) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisclosureOfSignificantAccountingPoliciesTable" xlink:label="fsm_DisclosureOfSignificantAccountingPoliciesTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" xlink:label="ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="fsm_DisclosureOfSignificantAccountingPoliciesTable" xlink:to="ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:label="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" xlink:to="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RestrictedShareUnitsMember" xlink:label="ifrs-full_RestrictedShareUnitsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:to="ifrs-full_RestrictedShareUnitsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PerformanceShareUnitsMember" xlink:label="fsm_PerformanceShareUnitsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:to="fsm_PerformanceShareUnitsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="fsm_DisclosureOfSignificantAccountingPoliciesTable" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningAssetsMember" xlink:label="ifrs-full_MiningAssetsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_MiningAssetsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningPropertyMember" xlink:label="ifrs-full_MiningPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningAssetsMember" xlink:to="ifrs-full_MiningPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CayllomaMeasuredAndIndicatedPropertyMember" xlink:label="fsm_CayllomaMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_CayllomaMeasuredAndIndicatedPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_YaramokoMeasuredAndIndicatedPropertyMember" xlink:label="fsm_YaramokoMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_YaramokoMeasuredAndIndicatedPropertyMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_SeguelaMeasuredAndIndicatedPropertyMember" xlink:label="fsm_SeguelaMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_SeguelaMeasuredAndIndicatedPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisclosureOfSignificantAccountingPoliciesLineItems" xlink:label="fsm_DisclosureOfSignificantAccountingPoliciesLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="fsm_DisclosureOfSignificantAccountingPoliciesLineItems" xlink:to="fsm_DisclosureOfSignificantAccountingPoliciesTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ConversionFactorsRelatedToInferredResources" xlink:label="fsm_ConversionFactorsRelatedToInferredResources" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="fsm_DisclosureOfSignificantAccountingPoliciesLineItems" xlink:to="fsm_ConversionFactorsRelatedToInferredResources" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PercentageOfInferredResources" xlink:label="fsm_PercentageOfInferredResources" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="fsm_DisclosureOfSignificantAccountingPoliciesLineItems" xlink:to="fsm_PercentageOfInferredResources" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ShareBasedArrangementVestingPeriod" xlink:label="fsm_ShareBasedArrangementVestingPeriod" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="fsm_DisclosureOfSignificantAccountingPoliciesLineItems" xlink:to="fsm_ShareBasedArrangementVestingPeriod" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureMaterialAccountingPoliciesDisclosureOfSubsidiariesDetails" xlink:type="extended" xlink:title="40302 - Disclosure - MATERIAL ACCOUNTING POLICIES (Disclosure of subsidiaries) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesTable" xlink:label="ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SignificantInvestmentsInSubsidiariesAxis" xlink:label="ifrs-full_SignificantInvestmentsInSubsidiariesAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesTable" xlink:to="ifrs-full_SignificantInvestmentsInSubsidiariesAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SignificantInvestmentsInSubsidiariesDomain" xlink:label="ifrs-full_SignificantInvestmentsInSubsidiariesDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_SignificantInvestmentsInSubsidiariesAxis" xlink:to="ifrs-full_SignificantInvestmentsInSubsidiariesDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SubsidiariesMember" xlink:label="ifrs-full_SubsidiariesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_SignificantInvestmentsInSubsidiariesDomain" xlink:to="ifrs-full_SubsidiariesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_MineraBateasS.a.c.Member" xlink:label="fsm_MineraBateasS.a.c.Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_SubsidiariesMember" xlink:to="fsm_MineraBateasS.a.c.Member" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CompaniaMineraCuzcatlanS.a.DeC.v.Member" xlink:label="fsm_CompaniaMineraCuzcatlanS.a.DeC.v.Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_SubsidiariesMember" xlink:to="fsm_CompaniaMineraCuzcatlanS.a.DeC.v.Member" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_MansfieldMineraS.a.Member" xlink:label="fsm_MansfieldMineraS.a.Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_SubsidiariesMember" xlink:to="fsm_MansfieldMineraS.a.Member" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_RoxgoldSanuS.a.SanuMember" xlink:label="fsm_RoxgoldSanuS.a.SanuMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_SubsidiariesMember" xlink:to="fsm_RoxgoldSanuS.a.SanuMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_RoxgoldSangoS.a.SangoMember" xlink:label="fsm_RoxgoldSangoS.a.SangoMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_SubsidiariesMember" xlink:to="fsm_RoxgoldSangoS.a.SangoMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_RoxgoldInc.Member" xlink:label="fsm_RoxgoldInc.Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_SubsidiariesMember" xlink:to="fsm_RoxgoldInc.Member" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_FrGoldMiningInc.Member" xlink:label="fsm_FrGoldMiningInc.Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_SubsidiariesMember" xlink:to="fsm_FrGoldMiningInc.Member" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_FortunaSilverMinesAustraliaPtyLtd.Member" xlink:label="fsm_FortunaSilverMinesAustraliaPtyLtd.Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_SubsidiariesMember" xlink:to="fsm_FortunaSilverMinesAustraliaPtyLtd.Member" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_LglExplorationCteDivoireSaMember" xlink:label="fsm_LglExplorationCteDivoireSaMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_SubsidiariesMember" xlink:to="fsm_LglExplorationCteDivoireSaMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_LglResourcesCteDivoireSaMember" xlink:label="fsm_LglResourcesCteDivoireSaMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="ifrs-full_SubsidiariesMember" xlink:to="fsm_LglResourcesCteDivoireSaMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_RoxgoldBoussouraSarlMember" xlink:label="fsm_RoxgoldBoussouraSarlMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="ifrs-full_SubsidiariesMember" xlink:to="fsm_RoxgoldBoussouraSarlMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesLineItems" xlink:label="ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesLineItems" xlink:to="ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NameOfSubsidiary" xlink:label="ifrs-full_NameOfSubsidiary" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesLineItems" xlink:to="ifrs-full_NameOfSubsidiary" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PrincipalPlaceOfBusinessOfSubsidiary" xlink:label="ifrs-full_PrincipalPlaceOfBusinessOfSubsidiary" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesLineItems" xlink:to="ifrs-full_PrincipalPlaceOfBusinessOfSubsidiary" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProportionOfOwnershipInterestInSubsidiary" xlink:label="ifrs-full_ProportionOfOwnershipInterestInSubsidiary" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesLineItems" xlink:to="ifrs-full_ProportionOfOwnershipInterestInSubsidiary" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PrincipalActivityOfSubsidiary" xlink:label="fsm_PrincipalActivityOfSubsidiary" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesLineItems" xlink:to="fsm_PrincipalActivityOfSubsidiary" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PrincipalActivityOfSubsidiaryTwo" xlink:label="fsm_PrincipalActivityOfSubsidiaryTwo" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesLineItems" xlink:to="fsm_PrincipalActivityOfSubsidiaryTwo" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DescriptionOfFunctionalCurrency" xlink:label="ifrs-full_DescriptionOfFunctionalCurrency" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesLineItems" xlink:to="ifrs-full_DescriptionOfFunctionalCurrency" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureMaterialAccountingPoliciesScheduleRelatedToPropertyPlantAndEquipmentDetails" xlink:type="extended" xlink:title="40303 - Disclosure - MATERIAL ACCOUNTING POLICIES (Schedule related to property, plant and equipment) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" xlink:label="ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LandAndBuildingsMember" xlink:label="ifrs-full_LandAndBuildingsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_LandAndBuildingsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LandMember" xlink:label="ifrs-full_LandMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_LandAndBuildingsMember" xlink:to="ifrs-full_LandMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BuildingsMember" xlink:label="ifrs-full_BuildingsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_LandAndBuildingsMember" xlink:to="ifrs-full_BuildingsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningAssetsMember" xlink:label="ifrs-full_MiningAssetsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_MiningAssetsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningPropertyMember" xlink:label="ifrs-full_MiningPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningAssetsMember" xlink:to="ifrs-full_MiningPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_BuildingsLocatedAtMineMember" xlink:label="fsm_BuildingsLocatedAtMineMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_MiningAssetsMember" xlink:to="fsm_BuildingsLocatedAtMineMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LeaseholdImprovementsMember" xlink:label="ifrs-full_LeaseholdImprovementsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_LeaseholdImprovementsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ProcessingPlantMember" xlink:label="fsm_ProcessingPlantMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="fsm_ProcessingPlantMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MachineryMember" xlink:label="ifrs-full_MachineryMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_MachineryMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_FurnitureAndOtherEquipmentsMember" xlink:label="fsm_FurnitureAndOtherEquipmentsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="fsm_FurnitureAndOtherEquipmentsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_VehiclesMember" xlink:label="ifrs-full_VehiclesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_VehiclesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ConstructionInProgressMember" xlink:label="ifrs-full_ConstructionInProgressMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_ConstructionInProgressMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeAxis" xlink:label="ifrs-full_RangeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" xlink:to="ifrs-full_RangeAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="ifrs-full_RangeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_RangeAxis" xlink:to="ifrs-full_RangeDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BottomOfRangeMember" xlink:label="ifrs-full_BottomOfRangeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_RangeDomain" xlink:to="ifrs-full_BottomOfRangeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TopOfRangeMember" xlink:label="ifrs-full_TopOfRangeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_RangeDomain" xlink:to="ifrs-full_TopOfRangeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:label="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MeasurementBasesPropertyPlantAndEquipment" xlink:label="ifrs-full_MeasurementBasesPropertyPlantAndEquipment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ifrs-full_MeasurementBasesPropertyPlantAndEquipment" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DepreciationMethodPropertyPlantAndEquipment" xlink:label="ifrs-full_DepreciationMethodPropertyPlantAndEquipment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ifrs-full_DepreciationMethodPropertyPlantAndEquipment" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UsefulLifeMeasuredAsPeriodOfTimePropertyPlantAndEquipment" xlink:label="ifrs-full_UsefulLifeMeasuredAsPeriodOfTimePropertyPlantAndEquipment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ifrs-full_UsefulLifeMeasuredAsPeriodOfTimePropertyPlantAndEquipment" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureUseOfEstimatesAssumptionsAndJudgementsNarrativeDetails" xlink:type="extended" xlink:title="40401 - Disclosure - USE OF ESTIMATES, ASSUMPTIONS, AND JUDGEMENTS (Narrative) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisclosureOfDetailedInformationAboutUseOfJudgementsAndEstimatesExplanatoryTable" xlink:label="fsm_DisclosureOfDetailedInformationAboutUseOfJudgementsAndEstimatesExplanatoryTable" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TypeOfCommodityAxis" xlink:label="fsm_TypeOfCommodityAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="fsm_DisclosureOfDetailedInformationAboutUseOfJudgementsAndEstimatesExplanatoryTable" xlink:to="fsm_TypeOfCommodityAxis" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TypeOfCommodityMember" xlink:label="fsm_TypeOfCommodityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="fsm_TypeOfCommodityAxis" xlink:to="fsm_TypeOfCommodityMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_GoldCommodityTypeMember" xlink:label="fsm_GoldCommodityTypeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="fsm_TypeOfCommodityMember" xlink:to="fsm_GoldCommodityTypeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_SilverCommodityTypeMember" xlink:label="fsm_SilverCommodityTypeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="fsm_TypeOfCommodityMember" xlink:to="fsm_SilverCommodityTypeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_LeadCommodityMember" xlink:label="fsm_LeadCommodityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="fsm_TypeOfCommodityMember" xlink:to="fsm_LeadCommodityMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ZincCommodityMember" xlink:label="fsm_ZincCommodityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="fsm_TypeOfCommodityMember" xlink:to="fsm_ZincCommodityMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="fsm_DisclosureOfDetailedInformationAboutUseOfJudgementsAndEstimatesExplanatoryTable" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningAssetsMember" xlink:label="ifrs-full_MiningAssetsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_MiningAssetsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningPropertyMember" xlink:label="ifrs-full_MiningPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningAssetsMember" xlink:to="ifrs-full_MiningPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_YaramokoMeasuredAndIndicatedPropertyMember" xlink:label="fsm_YaramokoMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_YaramokoMeasuredAndIndicatedPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisclosureOfDetailedInformationAboutUseOfJudgementsAndEstimatesExplanatoryLineItems" xlink:label="fsm_DisclosureOfDetailedInformationAboutUseOfJudgementsAndEstimatesExplanatoryLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="fsm_DisclosureOfDetailedInformationAboutUseOfJudgementsAndEstimatesExplanatoryLineItems" xlink:to="fsm_DisclosureOfDetailedInformationAboutUseOfJudgementsAndEstimatesExplanatoryTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_LongTermPricesUsedForReservesAndResourceEstimatesRelatedToCommodity" xlink:label="fsm_LongTermPricesUsedForReservesAndResourceEstimatesRelatedToCommodity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="fsm_DisclosureOfDetailedInformationAboutUseOfJudgementsAndEstimatesExplanatoryLineItems" xlink:to="fsm_LongTermPricesUsedForReservesAndResourceEstimatesRelatedToCommodity" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_LongTermPricesUsedForResourceEstimationRelatedToCommodity" xlink:label="fsm_LongTermPricesUsedForResourceEstimationRelatedToCommodity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="fsm_DisclosureOfDetailedInformationAboutUseOfJudgementsAndEstimatesExplanatoryLineItems" xlink:to="fsm_LongTermPricesUsedForResourceEstimationRelatedToCommodity" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureTradeAndOtherReceivablesScheduleOfTradeAndOtherReceivablesDetails" xlink:type="extended" xlink:title="40501 - Disclosure - TRADE AND OTHER RECEIVABLES (Schedule of Trade and Other Receivables) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOperatingSegmentsTable" xlink:label="ifrs-full_DisclosureOfOperatingSegmentsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasAxis" xlink:label="ifrs-full_GeographicalAreasAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsTable" xlink:to="ifrs-full_GeographicalAreasAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasDomain" xlink:label="ifrs-full_GeographicalAreasDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_GeographicalAreasAxis" xlink:to="ifrs-full_GeographicalAreasDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_AR" xlink:label="country_AR" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="country_AR" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_MX" xlink:label="country_MX" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="country_MX" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityAxis" xlink:label="ifrs-full_ComponentsOfEquityAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsTable" xlink:to="ifrs-full_ComponentsOfEquityAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ifrs-full_ComponentsOfEquityDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ComponentsOfEquityAxis" xlink:to="ifrs-full_ComponentsOfEquityDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncontrollingInterestsMember" xlink:label="ifrs-full_NoncontrollingInterestsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ComponentsOfEquityDomain" xlink:to="ifrs-full_NoncontrollingInterestsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_GovernmentOfBurkinaFasoMember" xlink:label="fsm_GovernmentOfBurkinaFasoMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_NoncontrollingInterestsMember" xlink:to="fsm_GovernmentOfBurkinaFasoMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_GovernmentOfCteDivoireMember" xlink:label="fsm_GovernmentOfCteDivoireMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_NoncontrollingInterestsMember" xlink:to="fsm_GovernmentOfCteDivoireMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:label="ifrs-full_DisclosureOfOperatingSegmentsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_DisclosureOfOperatingSegmentsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrentTradeReceivables" xlink:label="ifrs-full_CurrentTradeReceivables" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_CurrentTradeReceivables" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherCurrentReceivables" xlink:label="ifrs-full_OtherCurrentReceivables" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_OtherCurrentReceivables" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrentValueAddedTaxReceivables" xlink:label="ifrs-full_CurrentValueAddedTaxReceivables" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_CurrentValueAddedTaxReceivables" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TradeAndOtherCurrentReceivables" xlink:label="ifrs-full_TradeAndOtherCurrentReceivables" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_TradeAndOtherCurrentReceivables" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncurrentValueAddedTaxReceivables" xlink:label="ifrs-full_NoncurrentValueAddedTaxReceivables" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_NoncurrentValueAddedTaxReceivables" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ForeignExchangeGain" xlink:label="ifrs-full_ForeignExchangeGain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_ForeignExchangeGain" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_AdjustmentsForDecreaseIncreaseInValueAddedTaxesReceivables" xlink:label="fsm_AdjustmentsForDecreaseIncreaseInValueAddedTaxesReceivables" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="fsm_AdjustmentsForDecreaseIncreaseInValueAddedTaxesReceivables" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ValueAddedTaxDecreaseInReceivablesSoldFactorRate" xlink:label="fsm_ValueAddedTaxDecreaseInReceivablesSoldFactorRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="fsm_ValueAddedTaxDecreaseInReceivablesSoldFactorRate" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureInventoriesScheduleOfInventoriesDetails" xlink:type="extended" xlink:title="40601 - Disclosure - INVENTORIES (Schedule of Inventories) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOperatingSegmentsTable" xlink:label="ifrs-full_DisclosureOfOperatingSegmentsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentsAxis" xlink:label="ifrs-full_SegmentsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsTable" xlink:to="ifrs-full_SegmentsAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentsDomain" xlink:label="ifrs-full_SegmentsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_SegmentsAxis" xlink:to="ifrs-full_SegmentsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_LinderoAndYaramokoReportingSegmentMember" xlink:label="fsm_LinderoAndYaramokoReportingSegmentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_SegmentsDomain" xlink:to="fsm_LinderoAndYaramokoReportingSegmentMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:label="ifrs-full_DisclosureOfOperatingSegmentsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_DisclosureOfOperatingSegmentsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ConcentrateStockpiles" xlink:label="fsm_ConcentrateStockpiles" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="fsm_ConcentrateStockpiles" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CurrentDoreBarInventory" xlink:label="fsm_CurrentDoreBarInventory" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="fsm_CurrentDoreBarInventory" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_LeachPadAndCurrentGoldInCircuitInventory" xlink:label="fsm_LeachPadAndCurrentGoldInCircuitInventory" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="fsm_LeachPadAndCurrentGoldInCircuitInventory" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrentOreStockpiles" xlink:label="ifrs-full_CurrentOreStockpiles" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_CurrentOreStockpiles" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProductionSupplies" xlink:label="ifrs-full_ProductionSupplies" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_ProductionSupplies" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_InventoriesTotal" xlink:label="ifrs-full_InventoriesTotal" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_InventoriesTotal" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncurrentInventories" xlink:label="ifrs-full_NoncurrentInventories" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_NoncurrentInventories" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Inventories" xlink:label="ifrs-full_Inventories" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_Inventories" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CostOfInventoriesRecognisedAsExpenseDuringPeriod" xlink:label="ifrs-full_CostOfInventoriesRecognisedAsExpenseDuringPeriod" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_CostOfInventoriesRecognisedAsExpenseDuringPeriod" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_WritedownsReversalsOfInventories" xlink:label="ifrs-full_WritedownsReversalsOfInventories" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_WritedownsReversalsOfInventories" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DepreciationExpense" xlink:label="ifrs-full_DepreciationExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="12" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_DepreciationExpense" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureMineralPropertiesAndPropertyPlantAndEquipmentNarrativeDetails" xlink:type="extended" xlink:title="40801 - Disclosure - MINERAL PROPERTIES AND PROPERTY, PLANT AND EQUIPMENT (Narrative) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" xlink:label="ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" priority="8" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningAssetsMember" xlink:label="ifrs-full_MiningAssetsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_MiningAssetsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningPropertyMember" xlink:label="ifrs-full_MiningPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningAssetsMember" xlink:to="ifrs-full_MiningPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_SeguelaMeasuredAndIndicatedPropertyMember" xlink:label="fsm_SeguelaMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_SeguelaMeasuredAndIndicatedPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfAssetsAxis" xlink:label="ifrs-full_ClassesOfAssetsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" xlink:to="ifrs-full_ClassesOfAssetsAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfAssetsDomain" xlink:label="ifrs-full_ClassesOfAssetsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfAssetsAxis" xlink:to="ifrs-full_ClassesOfAssetsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_MineralPropertiesAndExplorationAndEvaluationAssetsMember" xlink:label="fsm_MineralPropertiesAndExplorationAndEvaluationAssetsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfAssetsDomain" xlink:to="fsm_MineralPropertiesAndExplorationAndEvaluationAssetsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_NonDepletableMember" xlink:label="fsm_NonDepletableMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="fsm_MineralPropertiesAndExplorationAndEvaluationAssetsMember" xlink:to="fsm_NonDepletableMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PropertyPlantAndEquipmentMember" xlink:label="ifrs-full_PropertyPlantAndEquipmentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_ClassesOfAssetsDomain" xlink:to="ifrs-full_PropertyPlantAndEquipmentMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:label="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_InterestCostsCapitalised" xlink:label="ifrs-full_InterestCostsCapitalised" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ifrs-full_InterestCostsCapitalised" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_NetSmelterReturnRoyaltyPercentage" xlink:label="fsm_NetSmelterReturnRoyaltyPercentage" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="fsm_NetSmelterReturnRoyaltyPercentage" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PurchaseAndSaleAgreementNetSmelterReturnPurchasePriceOfHalfOfRoyaltyPercentage" xlink:label="fsm_PurchaseAndSaleAgreementNetSmelterReturnPurchasePriceOfHalfOfRoyaltyPercentage" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="fsm_PurchaseAndSaleAgreementNetSmelterReturnPurchasePriceOfHalfOfRoyaltyPercentage" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherPropertyPlantAndEquipment" xlink:label="ifrs-full_OtherPropertyPlantAndEquipment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ifrs-full_OtherPropertyPlantAndEquipment" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RightofuseAssets" xlink:label="ifrs-full_RightofuseAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ifrs-full_RightofuseAssets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DepreciationRightofuseAssets" xlink:label="ifrs-full_DepreciationRightofuseAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ifrs-full_DepreciationRightofuseAssets" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureMineralPropertiesAndPropertyPlantAndEquipmentScheduleRelatedToPropertyPlantAndEquipmentDetails" xlink:type="extended" xlink:title="40802 - Disclosure - MINERAL PROPERTIES AND PROPERTY, PLANT AND EQUIPMENT (Schedule Related to Property, Plant and Equipment) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" xlink:label="ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningAssetsMember" xlink:label="ifrs-full_MiningAssetsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_MiningAssetsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningPropertyMember" xlink:label="ifrs-full_MiningPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningAssetsMember" xlink:to="ifrs-full_MiningPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ConstructionInProgressMember" xlink:label="ifrs-full_ConstructionInProgressMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_ConstructionInProgressMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherPropertyPlantAndEquipmentMember" xlink:label="ifrs-full_OtherPropertyPlantAndEquipmentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_OtherPropertyPlantAndEquipmentMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfAssetsAxis" xlink:label="ifrs-full_ClassesOfAssetsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" xlink:to="ifrs-full_ClassesOfAssetsAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfAssetsDomain" xlink:label="ifrs-full_ClassesOfAssetsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfAssetsAxis" xlink:to="ifrs-full_ClassesOfAssetsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_MineralPropertiesAndExplorationAndEvaluationAssetsMember" xlink:label="fsm_MineralPropertiesAndExplorationAndEvaluationAssetsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfAssetsDomain" xlink:to="fsm_MineralPropertiesAndExplorationAndEvaluationAssetsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DepletableMember" xlink:label="fsm_DepletableMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="fsm_MineralPropertiesAndExplorationAndEvaluationAssetsMember" xlink:to="fsm_DepletableMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_NonDepletableMember" xlink:label="fsm_NonDepletableMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="fsm_MineralPropertiesAndExplorationAndEvaluationAssetsMember" xlink:to="fsm_NonDepletableMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis" xlink:label="ifrs-full_CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="3" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" xlink:to="ifrs-full_CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CarryingAmountMember" xlink:label="ifrs-full_CarryingAmountMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis" xlink:to="ifrs-full_CarryingAmountMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GrossCarryingAmountMember" xlink:label="ifrs-full_GrossCarryingAmountMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_CarryingAmountMember" xlink:to="ifrs-full_GrossCarryingAmountMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AccumulatedDepreciationAmortisationAndImpairmentMember" xlink:label="ifrs-full_AccumulatedDepreciationAmortisationAndImpairmentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_CarryingAmountMember" xlink:to="ifrs-full_AccumulatedDepreciationAmortisationAndImpairmentMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:label="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PropertyPlantAndEquipmentIncludingRightofuseAssets" xlink:label="ifrs-full_PropertyPlantAndEquipmentIncludingRightofuseAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ifrs-full_PropertyPlantAndEquipmentIncludingRightofuseAssets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitionsThroughBusinessCombinationsPropertyPlantAndEquipment" xlink:label="ifrs-full_AcquisitionsThroughBusinessCombinationsPropertyPlantAndEquipment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ifrs-full_AcquisitionsThroughBusinessCombinationsPropertyPlantAndEquipment" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AdditionsOtherThanThroughBusinessCombinationsPropertyPlantAndEquipment" xlink:label="ifrs-full_AdditionsOtherThanThroughBusinessCombinationsPropertyPlantAndEquipment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ifrs-full_AdditionsOtherThanThroughBusinessCombinationsPropertyPlantAndEquipment" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncreaseDecreaseChangeInRehabilitationProvision" xlink:label="fsm_IncreaseDecreaseChangeInRehabilitationProvision" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="fsm_IncreaseDecreaseChangeInRehabilitationProvision" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisposalsAndWriteOffsOfPropertyPlantAndEquipment" xlink:label="fsm_DisposalsAndWriteOffsOfPropertyPlantAndEquipment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="fsm_DisposalsAndWriteOffsOfPropertyPlantAndEquipment" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ImpairmentLossRecognisedInProfitOrLossPropertyPlantAndEquipmentIncludingRightofuseAssets" xlink:label="ifrs-full_ImpairmentLossRecognisedInProfitOrLossPropertyPlantAndEquipmentIncludingRightofuseAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ifrs-full_ImpairmentLossRecognisedInProfitOrLossPropertyPlantAndEquipmentIncludingRightofuseAssets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughTransfersAndOtherChangesPropertyPlantAndEquipment" xlink:label="ifrs-full_IncreaseDecreaseThroughTransfersAndOtherChangesPropertyPlantAndEquipment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ifrs-full_IncreaseDecreaseThroughTransfersAndOtherChangesPropertyPlantAndEquipment" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DepreciationPropertyPlantAndEquipment" xlink:label="ifrs-full_DepreciationPropertyPlantAndEquipment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ifrs-full_DepreciationPropertyPlantAndEquipment" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PropertyPlantAndEquipmentNetBookValue" xlink:label="fsm_PropertyPlantAndEquipmentNetBookValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="fsm_PropertyPlantAndEquipmentNetBookValue" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DeferredTaxExpenseIncomeRelatingToOriginationAndReversalOfTemporaryDifferences" xlink:label="ifrs-full_DeferredTaxExpenseIncomeRelatingToOriginationAndReversalOfTemporaryDifferences" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ifrs-full_DeferredTaxExpenseIncomeRelatingToOriginationAndReversalOfTemporaryDifferences" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureOtherNonCurrentAssetsScheduleOfOtherAssetsDetails" xlink:type="extended" xlink:title="40901 - Disclosure - OTHER NON-CURRENT ASSETS (Schedule of other assets) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisclosureOfDetailedInformationAboutOtherNonCurrentAssetsTable" xlink:label="fsm_DisclosureOfDetailedInformationAboutOtherNonCurrentAssetsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="fsm_DisclosureOfDetailedInformationAboutOtherNonCurrentAssetsTable" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningAssetsMember" xlink:label="ifrs-full_MiningAssetsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_MiningAssetsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningPropertyMember" xlink:label="ifrs-full_MiningPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningAssetsMember" xlink:to="ifrs-full_MiningPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_LinderoProjectMember" xlink:label="fsm_LinderoProjectMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_LinderoProjectMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_SeguelaMeasuredAndIndicatedPropertyMember" xlink:label="fsm_SeguelaMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_SeguelaMeasuredAndIndicatedPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasAxis" xlink:label="ifrs-full_GeographicalAreasAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="fsm_DisclosureOfDetailedInformationAboutOtherNonCurrentAssetsTable" xlink:to="ifrs-full_GeographicalAreasAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasDomain" xlink:label="ifrs-full_GeographicalAreasDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_GeographicalAreasAxis" xlink:to="ifrs-full_GeographicalAreasDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_MX" xlink:label="country_MX" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="country_MX" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_BF" xlink:label="country_BF" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="country_BF" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisclosureOfDetailedInformationAboutOtherNonCurrentAssetsLineItems" xlink:label="fsm_DisclosureOfDetailedInformationAboutOtherNonCurrentAssetsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="fsm_DisclosureOfDetailedInformationAboutOtherNonCurrentAssetsLineItems" xlink:to="fsm_DisclosureOfDetailedInformationAboutOtherNonCurrentAssetsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncurrentOreStockpiles" xlink:label="ifrs-full_NoncurrentOreStockpiles" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="fsm_DisclosureOfDetailedInformationAboutOtherNonCurrentAssetsLineItems" xlink:to="ifrs-full_NoncurrentOreStockpiles" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_OtherAssetsValueAddedTaxReceivables" xlink:label="fsm_OtherAssetsValueAddedTaxReceivables" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="fsm_DisclosureOfDetailedInformationAboutOtherNonCurrentAssetsLineItems" xlink:to="fsm_OtherAssetsValueAddedTaxReceivables" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrentTaxAssetsNoncurrent" xlink:label="ifrs-full_CurrentTaxAssetsNoncurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="fsm_DisclosureOfDetailedInformationAboutOtherNonCurrentAssetsLineItems" xlink:to="ifrs-full_CurrentTaxAssetsNoncurrent" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_UnamortizedTransactionCostsAssets" xlink:label="fsm_UnamortizedTransactionCostsAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="fsm_DisclosureOfDetailedInformationAboutOtherNonCurrentAssetsLineItems" xlink:to="fsm_UnamortizedTransactionCostsAssets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherNoncurrentFinancialAssets" xlink:label="ifrs-full_OtherNoncurrentFinancialAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="fsm_DisclosureOfDetailedInformationAboutOtherNonCurrentAssetsLineItems" xlink:to="ifrs-full_OtherNoncurrentFinancialAssets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherNoncurrentReceivables" xlink:label="ifrs-full_OtherNoncurrentReceivables" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="fsm_DisclosureOfDetailedInformationAboutOtherNonCurrentAssetsLineItems" xlink:to="ifrs-full_OtherNoncurrentReceivables" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureTradeAndOtherPayablesScheduleOfTradeAndOtherPayablesDetails" xlink:type="extended" xlink:title="41001 - Disclosure - TRADE AND OTHER PAYABLES (Schedule of Trade and Other Payables) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CurrentLiabilitiesTable" xlink:label="fsm_CurrentLiabilitiesTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="fsm_CurrentLiabilitiesTable" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningAssetsMember" xlink:label="ifrs-full_MiningAssetsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_MiningAssetsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningPropertyMember" xlink:label="ifrs-full_MiningPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningAssetsMember" xlink:to="ifrs-full_MiningPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_SanJoseMineMember" xlink:label="fsm_SanJoseMineMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_SanJoseMineMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CurrentLiabilitiesLineItems" xlink:label="fsm_CurrentLiabilitiesLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="fsm_CurrentLiabilitiesLineItems" xlink:to="fsm_CurrentLiabilitiesTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TradeAndOtherPayablesToTradeSuppliers" xlink:label="ifrs-full_TradeAndOtherPayablesToTradeSuppliers" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="fsm_CurrentLiabilitiesLineItems" xlink:to="ifrs-full_TradeAndOtherPayablesToTradeSuppliers" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ShorttermEmployeeBenefitsAccruals" xlink:label="ifrs-full_ShorttermEmployeeBenefitsAccruals" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="fsm_CurrentLiabilitiesLineItems" xlink:to="ifrs-full_ShorttermEmployeeBenefitsAccruals" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_MiningRoyaltyPayable" xlink:label="fsm_MiningRoyaltyPayable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="fsm_CurrentLiabilitiesLineItems" xlink:to="fsm_MiningRoyaltyPayable" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherPayables" xlink:label="ifrs-full_OtherPayables" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="fsm_CurrentLiabilitiesLineItems" xlink:to="ifrs-full_OtherPayables" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DeferredShareUnitsPayable" xlink:label="fsm_DeferredShareUnitsPayable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="fsm_CurrentLiabilitiesLineItems" xlink:to="fsm_DeferredShareUnitsPayable" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrentDerivativeFinancialLiabilities" xlink:label="ifrs-full_CurrentDerivativeFinancialLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="fsm_CurrentLiabilitiesLineItems" xlink:to="ifrs-full_CurrentDerivativeFinancialLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TradeAndOtherCurrentPayables" xlink:label="ifrs-full_TradeAndOtherCurrentPayables" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="fsm_CurrentLiabilitiesLineItems" xlink:to="ifrs-full_TradeAndOtherCurrentPayables" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureLeaseObligationsScheduleOfLeaseObligationsDetails" xlink:type="extended" xlink:title="41201 - Disclosure - LEASE OBLIGATIONS (Schedule of Lease Obligations) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" xlink:label="ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MaturityAxis" xlink:label="ifrs-full_MaturityAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" xlink:to="ifrs-full_MaturityAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MaturityDomain" xlink:label="ifrs-full_MaturityDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_MaturityAxis" xlink:to="ifrs-full_MaturityDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NotLaterThanOneYearMember" xlink:label="ifrs-full_NotLaterThanOneYearMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MaturityDomain" xlink:to="ifrs-full_NotLaterThanOneYearMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LaterThanOneYearAndNotLaterThanFiveYearsMember" xlink:label="ifrs-full_LaterThanOneYearAndNotLaterThanFiveYearsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_MaturityDomain" xlink:to="ifrs-full_LaterThanOneYearAndNotLaterThanFiveYearsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LaterThanFiveYearsMember" xlink:label="ifrs-full_LaterThanFiveYearsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_MaturityDomain" xlink:to="ifrs-full_LaterThanFiveYearsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:label="ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GrossLeaseLiabilities" xlink:label="ifrs-full_GrossLeaseLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="ifrs-full_GrossLeaseLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_FutureFinanceChargeOnFinanceLeaseIfrs16" xlink:label="fsm_FutureFinanceChargeOnFinanceLeaseIfrs16" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="fsm_FutureFinanceChargeOnFinanceLeaseIfrs16" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_MinimumFinanceLeasePaymentsPayableAtPresentValueIfrs16" xlink:label="fsm_MinimumFinanceLeasePaymentsPayableAtPresentValueIfrs16" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="fsm_MinimumFinanceLeasePaymentsPayableAtPresentValueIfrs16" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrentLeaseLiabilities" xlink:label="ifrs-full_CurrentLeaseLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="ifrs-full_CurrentLeaseLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncurrentLeaseLiabilities" xlink:label="ifrs-full_NoncurrentLeaseLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="ifrs-full_NoncurrentLeaseLiabilities" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureDebtMovementInDebtDetails" xlink:type="extended" xlink:title="41301 - Disclosure - DEBT - Movement in debt (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:label="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameAxis" xlink:label="ifrs-full_BorrowingsByNameAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:to="ifrs-full_BorrowingsByNameAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameDomain" xlink:label="ifrs-full_BorrowingsByNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_BorrowingsByNameAxis" xlink:to="ifrs-full_BorrowingsByNameDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TermCreditFacilityMember" xlink:label="fsm_TermCreditFacilityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_BorrowingsByNameDomain" xlink:to="fsm_TermCreditFacilityMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebenturesMember" xlink:label="fsm_DebenturesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_BorrowingsByNameDomain" xlink:to="fsm_DebenturesMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ConvertibleNotes2024Member" xlink:label="fsm_ConvertibleNotes2024Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_BorrowingsByNameDomain" xlink:to="fsm_ConvertibleNotes2024Member" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:label="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LoansReceived" xlink:label="ifrs-full_LoansReceived" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ifrs-full_LoansReceived" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ProceedsFromIssueOfConvertibleNotes" xlink:label="fsm_ProceedsFromIssueOfConvertibleNotes" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_ProceedsFromIssueOfConvertibleNotes" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_LongTermBorrowingsReceived" xlink:label="fsm_LongTermBorrowingsReceived" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_LongTermBorrowingsReceived" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PaymentsForCostRelatedToConvertibleDebt" xlink:label="fsm_PaymentsForCostRelatedToConvertibleDebt" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_PaymentsForCostRelatedToConvertibleDebt" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebtInstrumentsConvertibleEquityComponent" xlink:label="fsm_DebtInstrumentsConvertibleEquityComponent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_DebtInstrumentsConvertibleEquityComponent" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncreaseDecreaseRelatedToConversionOfDebentures" xlink:label="fsm_IncreaseDecreaseRelatedToConversionOfDebentures" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_IncreaseDecreaseRelatedToConversionOfDebentures" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebtInstrumentsConvertibleTransactionCostEquityComponent" xlink:label="fsm_DebtInstrumentsConvertibleTransactionCostEquityComponent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_DebtInstrumentsConvertibleTransactionCostEquityComponent" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncreaseThroughAmortizationOfTransactionCosts" xlink:label="fsm_IncreaseThroughAmortizationOfTransactionCosts" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_IncreaseThroughAmortizationOfTransactionCosts" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ExtinguishmentOfDebt" xlink:label="fsm_ExtinguishmentOfDebt" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_ExtinguishmentOfDebt" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RepaymentsOfBorrowingsClassifiedAsFinancingActivities" xlink:label="ifrs-full_RepaymentsOfBorrowingsClassifiedAsFinancingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ifrs-full_RepaymentsOfBorrowingsClassifiedAsFinancingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_RepaymentsOfBorrowingsIncludingDebtExtinguishmentCosts" xlink:label="fsm_RepaymentsOfBorrowingsIncludingDebtExtinguishmentCosts" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="12" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_RepaymentsOfBorrowingsIncludingDebtExtinguishmentCosts" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncurrentPortionOfNoncurrentLoansReceived" xlink:label="ifrs-full_NoncurrentPortionOfNoncurrentLoansReceived" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="13" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ifrs-full_NoncurrentPortionOfNoncurrentLoansReceived" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureDebt2024ConvertibleNotesDetails" xlink:type="extended" xlink:title="41302 - Disclosure - DEBT - 2024 Convertible Notes (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:label="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameAxis" xlink:label="ifrs-full_BorrowingsByNameAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:to="ifrs-full_BorrowingsByNameAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameDomain" xlink:label="ifrs-full_BorrowingsByNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_BorrowingsByNameAxis" xlink:to="ifrs-full_BorrowingsByNameDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ConvertibleNotes2024Member" xlink:label="fsm_ConvertibleNotes2024Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_BorrowingsByNameDomain" xlink:to="fsm_ConvertibleNotes2024Member" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:label="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProceedsFromBorrowingsClassifiedAsFinancingActivities" xlink:label="ifrs-full_ProceedsFromBorrowingsClassifiedAsFinancingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ifrs-full_ProceedsFromBorrowingsClassifiedAsFinancingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PaymentsForDebtIssueCosts" xlink:label="ifrs-full_PaymentsForDebtIssueCosts" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ifrs-full_PaymentsForDebtIssueCosts" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsInterestRate" xlink:label="ifrs-full_BorrowingsInterestRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ifrs-full_BorrowingsInterestRate" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsDebtInstrumentConvertibleConversionRatio" xlink:label="fsm_IfrsDebtInstrumentConvertibleConversionRatio" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_IfrsDebtInstrumentConvertibleConversionRatio" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebtInstrumentPrincipalAmountDenominationForConversionIntoCommonStock" xlink:label="fsm_DebtInstrumentPrincipalAmountDenominationForConversionIntoCommonStock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_DebtInstrumentPrincipalAmountDenominationForConversionIntoCommonStock" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsDebtInstrumentConvertibleConversionPrice" xlink:label="fsm_IfrsDebtInstrumentConvertibleConversionPrice" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_IfrsDebtInstrumentConvertibleConversionPrice" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebtInstrumentRedemptionThresholdTradingDays" xlink:label="fsm_DebtInstrumentRedemptionThresholdTradingDays" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_DebtInstrumentRedemptionThresholdTradingDays" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebtInstrumentRedemptionThresholdConsecutiveTradingDays" xlink:label="fsm_DebtInstrumentRedemptionThresholdConsecutiveTradingDays" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_DebtInstrumentRedemptionThresholdConsecutiveTradingDays" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebtInstrumentRedemptionThresholdPercentageOfStockPriceTrigger" xlink:label="fsm_DebtInstrumentRedemptionThresholdPercentageOfStockPriceTrigger" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_DebtInstrumentRedemptionThresholdPercentageOfStockPriceTrigger" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsDebtInstrumentRedemptionPricePercentage" xlink:label="fsm_IfrsDebtInstrumentRedemptionPricePercentage" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_IfrsDebtInstrumentRedemptionPricePercentage" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebtInstrumentCashPurchasePricePercentageOfPrincipalAmountPlusAccruedInterestInEventOfFundamentalChange" xlink:label="fsm_DebtInstrumentCashPurchasePricePercentageOfPrincipalAmountPlusAccruedInterestInEventOfFundamentalChange" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="12" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_DebtInstrumentCashPurchasePricePercentageOfPrincipalAmountPlusAccruedInterestInEventOfFundamentalChange" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebtInstrumentConvertibleLiabilityComponent" xlink:label="fsm_DebtInstrumentConvertibleLiabilityComponent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="13" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_DebtInstrumentConvertibleLiabilityComponent" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebtInstrumentsConvertibleTransactionCostLiabilityComponent" xlink:label="fsm_DebtInstrumentsConvertibleTransactionCostLiabilityComponent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="14" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_DebtInstrumentsConvertibleTransactionCostLiabilityComponent" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebtInstrumentDiscountRateUsedForCalculationOfPresentValue" xlink:label="fsm_DebtInstrumentDiscountRateUsedForCalculationOfPresentValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="15" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_DebtInstrumentDiscountRateUsedForCalculationOfPresentValue" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebtInstrumentsConvertibleEquityComponent" xlink:label="fsm_DebtInstrumentsConvertibleEquityComponent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="16" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_DebtInstrumentsConvertibleEquityComponent" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebtInstrumentsConvertibleTransactionCostEquityComponent" xlink:label="fsm_DebtInstrumentsConvertibleTransactionCostEquityComponent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="17" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_DebtInstrumentsConvertibleTransactionCostEquityComponent" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DeferredTaxLiabilities" xlink:label="ifrs-full_DeferredTaxLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="18" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ifrs-full_DeferredTaxLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DeferredTaxAssets" xlink:label="ifrs-full_DeferredTaxAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="19" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ifrs-full_DeferredTaxAssets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_BorrowingsNet" xlink:label="fsm_BorrowingsNet" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="20" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_BorrowingsNet" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsDebtInstrumentInterestRateEffectivePercentage" xlink:label="fsm_IfrsDebtInstrumentInterestRateEffectivePercentage" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="21" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_IfrsDebtInstrumentInterestRateEffectivePercentage" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureDebt2019ConvertibleDebenturesDetails" xlink:type="extended" xlink:title="41303 - Disclosure - DEBT - 2019 Convertible Debentures (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:label="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameAxis" xlink:label="ifrs-full_BorrowingsByNameAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:to="ifrs-full_BorrowingsByNameAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameDomain" xlink:label="ifrs-full_BorrowingsByNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_BorrowingsByNameAxis" xlink:to="ifrs-full_BorrowingsByNameDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebenturesMember" xlink:label="fsm_DebenturesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_BorrowingsByNameDomain" xlink:to="fsm_DebenturesMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:label="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsInterestRate" xlink:label="ifrs-full_BorrowingsInterestRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ifrs-full_BorrowingsInterestRate" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_AmountDepositedInTrustRedemptionFunds" xlink:label="fsm_AmountDepositedInTrustRedemptionFunds" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_AmountDepositedInTrustRedemptionFunds" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RepaymentsOfBorrowingsClassifiedAsFinancingActivities" xlink:label="ifrs-full_RepaymentsOfBorrowingsClassifiedAsFinancingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ifrs-full_RepaymentsOfBorrowingsClassifiedAsFinancingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebtInstrumentRedemptionSettlementInShares" xlink:label="fsm_DebtInstrumentRedemptionSettlementInShares" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_DebtInstrumentRedemptionSettlementInShares" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsDebtConversionConvertedInstrumentSharesIssued" xlink:label="fsm_IfrsDebtConversionConvertedInstrumentSharesIssued" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_IfrsDebtConversionConvertedInstrumentSharesIssued" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsDebtInstrumentConvertibleConversionPrice" xlink:label="fsm_IfrsDebtInstrumentConvertibleConversionPrice" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_IfrsDebtInstrumentConvertibleConversionPrice" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebtInstrumentRedemptionPaymentOfAccruedInterest" xlink:label="fsm_DebtInstrumentRedemptionPaymentOfAccruedInterest" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_DebtInstrumentRedemptionPaymentOfAccruedInterest" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_AmountReceivedFromTrustRedemptionFunds" xlink:label="fsm_AmountReceivedFromTrustRedemptionFunds" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_AmountReceivedFromTrustRedemptionFunds" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureDebtCreditFacilitiesDetails" xlink:type="extended" xlink:title="41304 - Disclosure - DEBT - Credit Facilities (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:label="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameAxis" xlink:label="ifrs-full_BorrowingsByNameAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:to="ifrs-full_BorrowingsByNameAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameDomain" xlink:label="ifrs-full_BorrowingsByNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_BorrowingsByNameAxis" xlink:to="ifrs-full_BorrowingsByNameDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_AmendedCreditFacilityMember" xlink:label="fsm_AmendedCreditFacilityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_BorrowingsByNameDomain" xlink:to="fsm_AmendedCreditFacilityMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_AmendedSteppedDownCreditFacilityMember" xlink:label="fsm_AmendedSteppedDownCreditFacilityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_BorrowingsByNameDomain" xlink:to="fsm_AmendedSteppedDownCreditFacilityMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_AccordionOptionMember" xlink:label="fsm_AccordionOptionMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_BorrowingsByNameDomain" xlink:to="fsm_AccordionOptionMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeAxis" xlink:label="ifrs-full_RangeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:to="ifrs-full_RangeAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="ifrs-full_RangeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_RangeAxis" xlink:to="ifrs-full_RangeDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BottomOfRangeMember" xlink:label="ifrs-full_BottomOfRangeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_RangeDomain" xlink:to="ifrs-full_BottomOfRangeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TopOfRangeMember" xlink:label="ifrs-full_TopOfRangeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_RangeDomain" xlink:to="ifrs-full_TopOfRangeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfInterestRatesAxis" xlink:label="ifrs-full_TypesOfInterestRatesAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="3" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:to="ifrs-full_TypesOfInterestRatesAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfInterestRatesDomain" xlink:label="ifrs-full_TypesOfInterestRatesDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_TypesOfInterestRatesAxis" xlink:to="ifrs-full_TypesOfInterestRatesDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_LondonInterbankOfferedRateLiborMember" xlink:label="fsm_LondonInterbankOfferedRateLiborMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_TypesOfInterestRatesDomain" xlink:to="fsm_LondonInterbankOfferedRateLiborMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsSecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember" xlink:label="fsm_IfrsSecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_TypesOfInterestRatesDomain" xlink:to="fsm_IfrsSecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsBaseRateMember" xlink:label="fsm_IfrsBaseRateMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_TypesOfInterestRatesDomain" xlink:to="fsm_IfrsBaseRateMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" xlink:label="ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="4" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:to="ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" xlink:label="ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" xlink:to="ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisposalOfMajorSubsidiaryMember" xlink:label="ifrs-full_DisposalOfMajorSubsidiaryMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" xlink:to="ifrs-full_DisposalOfMajorSubsidiaryMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_StatementScenarioAxis" xlink:label="srt_StatementScenarioAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="5" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:to="srt_StatementScenarioAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="srt_ScenarioUnspecifiedDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="srt_StatementScenarioAxis" xlink:to="srt_ScenarioUnspecifiedDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_AfterThreeYearsMember" xlink:label="fsm_AfterThreeYearsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="srt_ScenarioUnspecifiedDomain" xlink:to="fsm_AfterThreeYearsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:label="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsLineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="fsm_IfrsLineOfCreditFacilityMaximumBorrowingCapacity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_IfrsLineOfCreditFacilityMaximumBorrowingCapacity" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsDebtInstrumentTerm" xlink:label="fsm_IfrsDebtInstrumentTerm" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_IfrsDebtInstrumentTerm" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsInterestRateBasis" xlink:label="ifrs-full_BorrowingsInterestRateBasis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ifrs-full_BorrowingsInterestRateBasis" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Borrowings" xlink:label="ifrs-full_Borrowings" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ifrs-full_Borrowings" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_BorrowingsIncreaseInInterestRateBasis" xlink:label="fsm_BorrowingsIncreaseInInterestRateBasis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_BorrowingsIncreaseInInterestRateBasis" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_BorrowingsIncreaseInCommitmentFeesInterestRate" xlink:label="fsm_BorrowingsIncreaseInCommitmentFeesInterestRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_BorrowingsIncreaseInCommitmentFeesInterestRate" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsAdjustmentToInterestRateBasis" xlink:label="ifrs-full_BorrowingsAdjustmentToInterestRateBasis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ifrs-full_BorrowingsAdjustmentToInterestRateBasis" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_BorrowingCovenantsTotalNetDebtToEarningsBeforeIncomeTaxesDepreciationAndAmortization" xlink:label="fsm_BorrowingCovenantsTotalNetDebtToEarningsBeforeIncomeTaxesDepreciationAndAmortization" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_BorrowingCovenantsTotalNetDebtToEarningsBeforeIncomeTaxesDepreciationAndAmortization" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_BorrowingCovenantsSeniorSecuredDebtTotalToEarningsBeforeIncomeTaxesDepreciationAndAmortization" xlink:label="fsm_BorrowingCovenantsSeniorSecuredDebtTotalToEarningsBeforeIncomeTaxesDepreciationAndAmortization" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_BorrowingCovenantsSeniorSecuredDebtTotalToEarningsBeforeIncomeTaxesDepreciationAndAmortization" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_BorrowingCovenantsEarningsBeforeIncomeTaxesDepreciationAndAmortizationToInterestExpenseRatio" xlink:label="fsm_BorrowingCovenantsEarningsBeforeIncomeTaxesDepreciationAndAmortizationToInterestExpenseRatio" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_BorrowingCovenantsEarningsBeforeIncomeTaxesDepreciationAndAmortizationToInterestExpenseRatio" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PercentageOfInterestDisposed" xlink:label="fsm_PercentageOfInterestDisposed" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="12" xlink:from="ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="fsm_PercentageOfInterestDisposed" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureOtherNonCurrentLiabilitiesScheduleOfOtherLiabilitiesDetails" xlink:type="extended" xlink:title="41401 - Disclosure - OTHER NON-CURRENT LIABILITIES (Schedule of Other Liabilities) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_OtherNonCurrentLiabilitiesTable" xlink:label="fsm_OtherNonCurrentLiabilitiesTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="fsm_OtherNonCurrentLiabilitiesTable" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningAssetsMember" xlink:label="ifrs-full_MiningAssetsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_MiningAssetsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningPropertyMember" xlink:label="ifrs-full_MiningPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningAssetsMember" xlink:to="ifrs-full_MiningPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_SanJoseMineMember" xlink:label="fsm_SanJoseMineMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_SanJoseMineMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_OtherNonCurrentLiabilitiesLineItems" xlink:label="fsm_OtherNonCurrentLiabilitiesLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="fsm_OtherNonCurrentLiabilitiesLineItems" xlink:to="fsm_OtherNonCurrentLiabilitiesTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_RestrictedShareUnitsObligation" xlink:label="fsm_RestrictedShareUnitsObligation" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="fsm_OtherNonCurrentLiabilitiesLineItems" xlink:to="fsm_RestrictedShareUnitsObligation" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherNoncurrentLiabilities" xlink:label="ifrs-full_OtherNoncurrentLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="fsm_OtherNonCurrentLiabilitiesLineItems" xlink:to="ifrs-full_OtherNoncurrentLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherLiabilities" xlink:label="ifrs-full_OtherLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="fsm_OtherNonCurrentLiabilitiesLineItems" xlink:to="ifrs-full_OtherLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LongtermRestructuringProvision" xlink:label="ifrs-full_LongtermRestructuringProvision" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="fsm_OtherNonCurrentLiabilitiesLineItems" xlink:to="ifrs-full_LongtermRestructuringProvision" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureClosureAndReclamationProvisionsScheduleOfClosureAndRehabilitationProvisionsDetails" xlink:type="extended" xlink:title="41501 - Disclosure - CLOSURE AND RECLAMATION PROVISIONS (Schedule of Closure and Rehabilitation Provisions) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOtherProvisionsTable" xlink:label="ifrs-full_DisclosureOfOtherProvisionsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfOtherProvisionsTable" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningAssetsMember" xlink:label="ifrs-full_MiningAssetsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_MiningAssetsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningPropertyMember" xlink:label="ifrs-full_MiningPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningAssetsMember" xlink:to="ifrs-full_MiningPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CayllomaMeasuredAndIndicatedPropertyMember" xlink:label="fsm_CayllomaMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_CayllomaMeasuredAndIndicatedPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_SanJoseMeasuredAndIndicatedPropertyMember" xlink:label="fsm_SanJoseMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_SanJoseMeasuredAndIndicatedPropertyMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_LinderoProjectMember" xlink:label="fsm_LinderoProjectMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_LinderoProjectMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_YaramokoMeasuredAndIndicatedPropertyMember" xlink:label="fsm_YaramokoMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_YaramokoMeasuredAndIndicatedPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_SeguelaMeasuredAndIndicatedPropertyMember" xlink:label="fsm_SeguelaMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_SeguelaMeasuredAndIndicatedPropertyMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfProvisionsAxis" xlink:label="ifrs-full_ClassesOfProvisionsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="ifrs-full_DisclosureOfOtherProvisionsTable" xlink:to="ifrs-full_ClassesOfProvisionsAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfOtherProvisionsDomain" xlink:label="ifrs-full_ClassesOfOtherProvisionsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfProvisionsAxis" xlink:to="ifrs-full_ClassesOfOtherProvisionsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProvisionForDecommissioningRestorationAndRehabilitationCostsMember" xlink:label="ifrs-full_ProvisionForDecommissioningRestorationAndRehabilitationCostsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfOtherProvisionsDomain" xlink:to="ifrs-full_ProvisionForDecommissioningRestorationAndRehabilitationCostsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:label="ifrs-full_DisclosureOfOtherProvisionsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="ifrs-full_DisclosureOfOtherProvisionsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherProvisions" xlink:label="ifrs-full_OtherProvisions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="ifrs-full_OtherProvisions" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughTransfersAndOtherChangesOtherProvisions" xlink:label="ifrs-full_IncreaseDecreaseThroughTransfersAndOtherChangesOtherProvisions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="ifrs-full_IncreaseDecreaseThroughTransfersAndOtherChangesOtherProvisions" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProvisionUsedOtherProvisions" xlink:label="ifrs-full_ProvisionUsedOtherProvisions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="ifrs-full_ProvisionUsedOtherProvisions" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughTimeValueOfMoneyAdjustmentOtherProvisions" xlink:label="ifrs-full_IncreaseDecreaseThroughTimeValueOfMoneyAdjustmentOtherProvisions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="ifrs-full_IncreaseDecreaseThroughTimeValueOfMoneyAdjustmentOtherProvisions" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughNetExchangeDifferencesOtherProvisions" xlink:label="ifrs-full_IncreaseDecreaseThroughNetExchangeDifferencesOtherProvisions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="ifrs-full_IncreaseDecreaseThroughNetExchangeDifferencesOtherProvisions" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CurrentProvisionForAssetRetirementObligation" xlink:label="fsm_CurrentProvisionForAssetRetirementObligation" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="fsm_CurrentProvisionForAssetRetirementObligation" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_NoncurrentProvisionForAssetRetirementObligation" xlink:label="fsm_NoncurrentProvisionForAssetRetirementObligation" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="fsm_NoncurrentProvisionForAssetRetirementObligation" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureClosureAndReclamationProvisionsScheduleOfEstimatesUsedInClosureAndRehabilitationProvisionsDetails" xlink:type="extended" xlink:title="41502 - Disclosure - CLOSURE AND RECLAMATION PROVISIONS (Schedule of Estimates Used in Closure and Rehabilitation Provisions) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOtherProvisionsTable" xlink:label="ifrs-full_DisclosureOfOtherProvisionsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfOtherProvisionsTable" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningAssetsMember" xlink:label="ifrs-full_MiningAssetsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_MiningAssetsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningPropertyMember" xlink:label="ifrs-full_MiningPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningAssetsMember" xlink:to="ifrs-full_MiningPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CayllomaMeasuredAndIndicatedPropertyMember" xlink:label="fsm_CayllomaMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_CayllomaMeasuredAndIndicatedPropertyMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_SanJoseMeasuredAndIndicatedPropertyMember" xlink:label="fsm_SanJoseMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_SanJoseMeasuredAndIndicatedPropertyMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_LinderoProjectMember" xlink:label="fsm_LinderoProjectMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_LinderoProjectMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_YaramokoMeasuredAndIndicatedPropertyMember" xlink:label="fsm_YaramokoMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_YaramokoMeasuredAndIndicatedPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_SeguelaMeasuredAndIndicatedPropertyMember" xlink:label="fsm_SeguelaMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_SeguelaMeasuredAndIndicatedPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfProvisionsAxis" xlink:label="ifrs-full_ClassesOfProvisionsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="ifrs-full_DisclosureOfOtherProvisionsTable" xlink:to="ifrs-full_ClassesOfProvisionsAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfOtherProvisionsDomain" xlink:label="ifrs-full_ClassesOfOtherProvisionsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfProvisionsAxis" xlink:to="ifrs-full_ClassesOfOtherProvisionsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProvisionForDecommissioningRestorationAndRehabilitationCostsMember" xlink:label="ifrs-full_ProvisionForDecommissioningRestorationAndRehabilitationCostsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfOtherProvisionsDomain" xlink:to="ifrs-full_ProvisionForDecommissioningRestorationAndRehabilitationCostsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:label="ifrs-full_DisclosureOfOtherProvisionsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="ifrs-full_DisclosureOfOtherProvisionsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_OtherProvisionsUndiscountedCashFlows" xlink:label="fsm_OtherProvisionsUndiscountedCashFlows" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="fsm_OtherProvisionsUndiscountedCashFlows" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_MajorAssumptionsMadeConcerningFutureEventsOtherProvisionsDiscountRate" xlink:label="fsm_MajorAssumptionsMadeConcerningFutureEventsOtherProvisionsDiscountRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="fsm_MajorAssumptionsMadeConcerningFutureEventsOtherProvisionsDiscountRate" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_MajorAssumptionsMadeConcerningFutureEventsOtherProvisionsInflationRate" xlink:label="fsm_MajorAssumptionsMadeConcerningFutureEventsOtherProvisionsInflationRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="fsm_MajorAssumptionsMadeConcerningFutureEventsOtherProvisionsInflationRate" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureShareBasedPaymentsNarrativeDetails" xlink:type="extended" xlink:title="41601 - Disclosure - SHARE-BASED PAYMENTS (Narrative) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:label="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeAxis" xlink:label="ifrs-full_RangeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:to="ifrs-full_RangeAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="ifrs-full_RangeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_RangeAxis" xlink:to="ifrs-full_RangeDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TopOfRangeMember" xlink:label="ifrs-full_TopOfRangeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_RangeDomain" xlink:to="ifrs-full_TopOfRangeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" xlink:label="ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:to="ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:label="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" xlink:to="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DeferredRestrictedAndPerformanceShareUnitsMember" xlink:label="fsm_DeferredRestrictedAndPerformanceShareUnitsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:to="fsm_DeferredRestrictedAndPerformanceShareUnitsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RestrictedShareUnitsMember" xlink:label="ifrs-full_RestrictedShareUnitsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:to="ifrs-full_RestrictedShareUnitsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PerformanceShareUnitsMember" xlink:label="fsm_PerformanceShareUnitsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:to="fsm_PerformanceShareUnitsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsShareBasedPaymentArrangementOptionMember" xlink:label="fsm_IfrsShareBasedPaymentArrangementOptionMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:to="fsm_IfrsShareBasedPaymentArrangementOptionMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:label="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ExpenseFromSharebasedPaymentTransactionsWithEmployees" xlink:label="ifrs-full_ExpenseFromSharebasedPaymentTransactionsWithEmployees" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ifrs-full_ExpenseFromSharebasedPaymentTransactionsWithEmployees" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_FairValueOfNumberOfOtherEquityInstrumentsGrantedInShareBasedPaymentArrangement" xlink:label="fsm_FairValueOfNumberOfOtherEquityInstrumentsGrantedInShareBasedPaymentArrangement" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="fsm_FairValueOfNumberOfOtherEquityInstrumentsGrantedInShareBasedPaymentArrangement" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:label="fsm_IfrsShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="fsm_IfrsShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:label="fsm_IfrsShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="fsm_IfrsShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureShareBasedPaymentsScheduleOfOutstandingUnitsActivityDetails" xlink:type="extended" xlink:title="41602 - Disclosure - SHARE-BASED PAYMENTS (Schedule of Outstanding Units Activity) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:label="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" xlink:label="ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:to="ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:label="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" xlink:to="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DeferredShareUnitsMember" xlink:label="fsm_DeferredShareUnitsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:to="fsm_DeferredShareUnitsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RestrictedShareUnitsMember" xlink:label="ifrs-full_RestrictedShareUnitsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:to="ifrs-full_RestrictedShareUnitsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CashSettledRestrictedShareUnitsMember" xlink:label="fsm_CashSettledRestrictedShareUnitsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_RestrictedShareUnitsMember" xlink:to="fsm_CashSettledRestrictedShareUnitsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_EquitySettledRestrictedShareUnitsMember" xlink:label="fsm_EquitySettledRestrictedShareUnitsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_RestrictedShareUnitsMember" xlink:to="fsm_EquitySettledRestrictedShareUnitsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PerformanceShareUnitsMember" xlink:label="fsm_PerformanceShareUnitsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:to="fsm_PerformanceShareUnitsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CashSettledPerformanceShareUnitsMember" xlink:label="fsm_CashSettledPerformanceShareUnitsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="fsm_PerformanceShareUnitsMember" xlink:to="fsm_CashSettledPerformanceShareUnitsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_EquitySettledPerformanceShareUnitsMember" xlink:label="fsm_EquitySettledPerformanceShareUnitsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="fsm_PerformanceShareUnitsMember" xlink:to="fsm_EquitySettledPerformanceShareUnitsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:label="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfOtherEquityInstrumentsOutstandingInSharebasedPaymentArrangement" xlink:label="ifrs-full_NumberOfOtherEquityInstrumentsOutstandingInSharebasedPaymentArrangement" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ifrs-full_NumberOfOtherEquityInstrumentsOutstandingInSharebasedPaymentArrangement" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfInstrumentsOtherEquityInstrumentsGranted" xlink:label="ifrs-full_NumberOfInstrumentsOtherEquityInstrumentsGranted" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ifrs-full_NumberOfInstrumentsOtherEquityInstrumentsGranted" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfOtherEquityInstrumentsExercisedOrVestedInSharebasedPaymentArrangement" xlink:label="ifrs-full_NumberOfOtherEquityInstrumentsExercisedOrVestedInSharebasedPaymentArrangement" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ifrs-full_NumberOfOtherEquityInstrumentsExercisedOrVestedInSharebasedPaymentArrangement" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfOtherEquityInstrumentsForfeitedInSharebasedPaymentArrangement" xlink:label="ifrs-full_NumberOfOtherEquityInstrumentsForfeitedInSharebasedPaymentArrangement" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ifrs-full_NumberOfOtherEquityInstrumentsForfeitedInSharebasedPaymentArrangement" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_NumberOfInstrumentsOtherEquityInstrumentsTransferredFromEquityToCashSettled" xlink:label="fsm_NumberOfInstrumentsOtherEquityInstrumentsTransferredFromEquityToCashSettled" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="fsm_NumberOfInstrumentsOtherEquityInstrumentsTransferredFromEquityToCashSettled" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_FairValueOfOtherEquityInstrumentsInSharebasedPaymentArrangementOutstanding" xlink:label="fsm_FairValueOfOtherEquityInstrumentsInSharebasedPaymentArrangementOutstanding" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="fsm_FairValueOfOtherEquityInstrumentsInSharebasedPaymentArrangementOutstanding" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_FairValueOfOtherEquityInstrumentsInSharebasedPaymentArrangementGranted" xlink:label="fsm_FairValueOfOtherEquityInstrumentsInSharebasedPaymentArrangementGranted" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="fsm_FairValueOfOtherEquityInstrumentsInSharebasedPaymentArrangementGranted" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_FairValueOfOtherEquityInstrumentsInShareBasedPaymentArrangementForfeitedOrCancelled" xlink:label="fsm_FairValueOfOtherEquityInstrumentsInShareBasedPaymentArrangementForfeitedOrCancelled" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="fsm_FairValueOfOtherEquityInstrumentsInShareBasedPaymentArrangementForfeitedOrCancelled" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_FairValueOfOtherEquityInstrumentsInSharebasedPaymentArrangementPaidInCash" xlink:label="fsm_FairValueOfOtherEquityInstrumentsInSharebasedPaymentArrangementPaidInCash" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="fsm_FairValueOfOtherEquityInstrumentsInSharebasedPaymentArrangementPaidInCash" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_FairValueIncreaseDecreaseInOtherUnits" xlink:label="fsm_FairValueIncreaseDecreaseInOtherUnits" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="fsm_FairValueIncreaseDecreaseInOtherUnits" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_FairValueOfOtherEquityInstrumentsInShareBasedPaymentArrangementOutstandingCurrent" xlink:label="fsm_FairValueOfOtherEquityInstrumentsInShareBasedPaymentArrangementOutstandingCurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="12" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="fsm_FairValueOfOtherEquityInstrumentsInShareBasedPaymentArrangementOutstandingCurrent" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_FairValueOfOtherEquityInstrumentsInShareBasedPaymentArrangementOutstandingNonCurrent" xlink:label="fsm_FairValueOfOtherEquityInstrumentsInShareBasedPaymentArrangementOutstandingNonCurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="13" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="fsm_FairValueOfOtherEquityInstrumentsInShareBasedPaymentArrangementOutstandingNonCurrent" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureShareBasedPaymentsScheduleOfOutstandingOptionActivityDetails" xlink:type="extended" xlink:title="41603 - Disclosure - SHARE-BASED PAYMENTS (Schedule of Outstanding Option Activity) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:label="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" xlink:label="ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:to="ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:label="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" xlink:to="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsShareBasedPaymentArrangementOptionMember" xlink:label="fsm_IfrsShareBasedPaymentArrangementOptionMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:to="fsm_IfrsShareBasedPaymentArrangementOptionMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:label="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfOutstandingShareOptions" xlink:label="ifrs-full_NumberOfOutstandingShareOptions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ifrs-full_NumberOfOutstandingShareOptions" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfShareOptionsExercisedInSharebasedPaymentArrangement" xlink:label="ifrs-full_NumberOfShareOptionsExercisedInSharebasedPaymentArrangement" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ifrs-full_NumberOfShareOptionsExercisedInSharebasedPaymentArrangement" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfShareOptionsExpiredInSharebasedPaymentArrangement" xlink:label="ifrs-full_NumberOfShareOptionsExpiredInSharebasedPaymentArrangement" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ifrs-full_NumberOfShareOptionsExpiredInSharebasedPaymentArrangement" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_WeightedAverageExercisePriceOfShareOptionsOutstandingInSharebasedPaymentArrangement2019" xlink:label="ifrs-full_WeightedAverageExercisePriceOfShareOptionsOutstandingInSharebasedPaymentArrangement2019" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ifrs-full_WeightedAverageExercisePriceOfShareOptionsOutstandingInSharebasedPaymentArrangement2019" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_WeightedAverageExercisePriceOfShareOptionsExercisedInSharebasedPaymentArrangement2019" xlink:label="ifrs-full_WeightedAverageExercisePriceOfShareOptionsExercisedInSharebasedPaymentArrangement2019" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ifrs-full_WeightedAverageExercisePriceOfShareOptionsExercisedInSharebasedPaymentArrangement2019" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_WeightedAverageExercisePriceOfShareOptionsExpiredInSharebasedPaymentArrangement2019" xlink:label="ifrs-full_WeightedAverageExercisePriceOfShareOptionsExpiredInSharebasedPaymentArrangement2019" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ifrs-full_WeightedAverageExercisePriceOfShareOptionsExpiredInSharebasedPaymentArrangement2019" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureSalesScheduleOfSalesByProductAndGeographicalAreaDetails" xlink:type="extended" xlink:title="41901 - Disclosure - SALES (Schedule of Sales by Product and Geographical Area) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfGeographicalAreasTable" xlink:label="ifrs-full_DisclosureOfGeographicalAreasTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasAxis" xlink:label="ifrs-full_GeographicalAreasAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfGeographicalAreasTable" xlink:to="ifrs-full_GeographicalAreasAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasDomain" xlink:label="ifrs-full_GeographicalAreasDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_GeographicalAreasAxis" xlink:to="ifrs-full_GeographicalAreasDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ForeignCountriesMember" xlink:label="ifrs-full_ForeignCountriesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="ifrs-full_ForeignCountriesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_PE" xlink:label="country_PE" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ForeignCountriesMember" xlink:to="country_PE" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_MX" xlink:label="country_MX" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_ForeignCountriesMember" xlink:to="country_MX" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_AR" xlink:label="country_AR" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_ForeignCountriesMember" xlink:to="country_AR" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_BF" xlink:label="country_BF" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_ForeignCountriesMember" xlink:to="country_BF" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_CI" xlink:label="country_CI" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_ForeignCountriesMember" xlink:to="country_CI" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProductsAndServicesAxis" xlink:label="ifrs-full_ProductsAndServicesAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="ifrs-full_DisclosureOfGeographicalAreasTable" xlink:to="ifrs-full_ProductsAndServicesAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProductsAndServicesDomain" xlink:label="ifrs-full_ProductsAndServicesDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ProductsAndServicesAxis" xlink:to="ifrs-full_ProductsAndServicesDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_SilverGoldConcentratesMember" xlink:label="fsm_SilverGoldConcentratesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ProductsAndServicesDomain" xlink:to="fsm_SilverGoldConcentratesMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_SilverLeadConcentratesMember" xlink:label="fsm_SilverLeadConcentratesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_ProductsAndServicesDomain" xlink:to="fsm_SilverLeadConcentratesMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ZincConcentratesMember" xlink:label="fsm_ZincConcentratesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_ProductsAndServicesDomain" xlink:to="fsm_ZincConcentratesMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_GoldDoreMember" xlink:label="fsm_GoldDoreMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_ProductsAndServicesDomain" xlink:to="fsm_GoldDoreMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ProvisionalPricingAdjustmentsMember" xlink:label="fsm_ProvisionalPricingAdjustmentsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_ProductsAndServicesDomain" xlink:to="fsm_ProvisionalPricingAdjustmentsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfGeographicalAreasLineItems" xlink:label="ifrs-full_DisclosureOfGeographicalAreasLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfGeographicalAreasLineItems" xlink:to="ifrs-full_DisclosureOfGeographicalAreasTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Revenue" xlink:label="ifrs-full_Revenue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfGeographicalAreasLineItems" xlink:to="ifrs-full_Revenue" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsGainLossOnSaleOfDerivatives" xlink:label="fsm_IfrsGainLossOnSaleOfDerivatives" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfGeographicalAreasLineItems" xlink:to="fsm_IfrsGainLossOnSaleOfDerivatives" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GainsLossesOnChangeInFairValueOfDerivatives" xlink:label="ifrs-full_GainsLossesOnChangeInFairValueOfDerivatives" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfGeographicalAreasLineItems" xlink:to="ifrs-full_GainsLossesOnChangeInFairValueOfDerivatives" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureSalesScheduleOfSalesByMajorCustomerDetails" xlink:type="extended" xlink:title="41902 - Disclosure - SALES (Schedule of Sales by Major Customer) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfMajorCustomersTable" xlink:label="ifrs-full_DisclosureOfMajorCustomersTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MajorCustomersAxis" xlink:label="ifrs-full_MajorCustomersAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfMajorCustomersTable" xlink:to="ifrs-full_MajorCustomersAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MajorCustomersDomain" xlink:label="ifrs-full_MajorCustomersDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_MajorCustomersAxis" xlink:to="ifrs-full_MajorCustomersDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CustomerOneMember" xlink:label="fsm_CustomerOneMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MajorCustomersDomain" xlink:to="fsm_CustomerOneMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CustomerTwoMember" xlink:label="fsm_CustomerTwoMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_MajorCustomersDomain" xlink:to="fsm_CustomerTwoMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CustomerThreeMember" xlink:label="fsm_CustomerThreeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_MajorCustomersDomain" xlink:to="fsm_CustomerThreeMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CustomerFourMember" xlink:label="fsm_CustomerFourMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_MajorCustomersDomain" xlink:to="fsm_CustomerFourMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CustomerFiveMember" xlink:label="fsm_CustomerFiveMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_MajorCustomersDomain" xlink:to="fsm_CustomerFiveMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CustomerSixMember" xlink:label="fsm_CustomerSixMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_MajorCustomersDomain" xlink:to="fsm_CustomerSixMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfMajorCustomersLineItems" xlink:label="ifrs-full_DisclosureOfMajorCustomersLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfMajorCustomersLineItems" xlink:to="ifrs-full_DisclosureOfMajorCustomersTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Revenue" xlink:label="ifrs-full_Revenue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfMajorCustomersLineItems" xlink:to="ifrs-full_Revenue" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureOtherExpensesAdditionalInformationDetails" xlink:type="extended" xlink:title="42202 - Disclosure - OTHER EXPENSES - Additional information (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfAttributionOfExpensesByNatureToTheirFunctionTable" xlink:label="ifrs-full_DisclosureOfAttributionOfExpensesByNatureToTheirFunctionTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AttributionOfExpensesByNatureToTheirFunctionAxis" xlink:label="ifrs-full_AttributionOfExpensesByNatureToTheirFunctionAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfAttributionOfExpensesByNatureToTheirFunctionTable" xlink:to="ifrs-full_AttributionOfExpensesByNatureToTheirFunctionAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AttributionOfExpensesByNatureToTheirFunctionDomain" xlink:label="ifrs-full_AttributionOfExpensesByNatureToTheirFunctionDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_AttributionOfExpensesByNatureToTheirFunctionAxis" xlink:to="ifrs-full_AttributionOfExpensesByNatureToTheirFunctionDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ChangeInClosureAndReclamationEstimateOfSanJoseMineMember" xlink:label="fsm_ChangeInClosureAndReclamationEstimateOfSanJoseMineMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_AttributionOfExpensesByNatureToTheirFunctionDomain" xlink:to="fsm_ChangeInClosureAndReclamationEstimateOfSanJoseMineMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ExplorationCostsMember" xlink:label="fsm_ExplorationCostsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_AttributionOfExpensesByNatureToTheirFunctionDomain" xlink:to="fsm_ExplorationCostsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_WithholdingTaxProvisionsMember" xlink:label="fsm_WithholdingTaxProvisionsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_AttributionOfExpensesByNatureToTheirFunctionDomain" xlink:to="fsm_WithholdingTaxProvisionsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_AdministrativePenaltiesAtYaramokoMember" xlink:label="fsm_AdministrativePenaltiesAtYaramokoMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_AttributionOfExpensesByNatureToTheirFunctionDomain" xlink:to="fsm_AdministrativePenaltiesAtYaramokoMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_StandByAndMaintenanceCostsDuringWorkStoppagesAtYaramokoAndSanJoseMember" xlink:label="fsm_StandByAndMaintenanceCostsDuringWorkStoppagesAtYaramokoAndSanJoseMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_AttributionOfExpensesByNatureToTheirFunctionDomain" xlink:to="fsm_StandByAndMaintenanceCostsDuringWorkStoppagesAtYaramokoAndSanJoseMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_NewAgreementWithWorkersUnionAtSanJoseMember" xlink:label="fsm_NewAgreementWithWorkersUnionAtSanJoseMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_AttributionOfExpensesByNatureToTheirFunctionDomain" xlink:to="fsm_NewAgreementWithWorkersUnionAtSanJoseMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfAttributionOfExpensesByNatureToTheirFunctionLineItems" xlink:label="ifrs-full_DisclosureOfAttributionOfExpensesByNatureToTheirFunctionLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfAttributionOfExpensesByNatureToTheirFunctionLineItems" xlink:to="ifrs-full_DisclosureOfAttributionOfExpensesByNatureToTheirFunctionTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiscellaneousOtherOperatingExpense" xlink:label="ifrs-full_MiscellaneousOtherOperatingExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfAttributionOfExpensesByNatureToTheirFunctionLineItems" xlink:to="ifrs-full_MiscellaneousOtherOperatingExpense" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureInterestAndFinanceCostsNetDetails" xlink:type="extended" xlink:title="42301 - Disclosure - INTEREST AND FINANCE COSTS, NET (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOtherProvisionsTable" xlink:label="ifrs-full_DisclosureOfOtherProvisionsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameAxis" xlink:label="ifrs-full_BorrowingsByNameAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfOtherProvisionsTable" xlink:to="ifrs-full_BorrowingsByNameAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameDomain" xlink:label="ifrs-full_BorrowingsByNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_BorrowingsByNameAxis" xlink:to="ifrs-full_BorrowingsByNameDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TermCreditFacilityMember" xlink:label="fsm_TermCreditFacilityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_BorrowingsByNameDomain" xlink:to="fsm_TermCreditFacilityMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebenturesMember" xlink:label="fsm_DebenturesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_BorrowingsByNameDomain" xlink:to="fsm_DebenturesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ConvertibleNotes2024Member" xlink:label="fsm_ConvertibleNotes2024Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_BorrowingsByNameDomain" xlink:to="fsm_ConvertibleNotes2024Member" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:label="ifrs-full_DisclosureOfOtherProvisionsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="ifrs-full_DisclosureOfOtherProvisionsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RevenueFromInterest" xlink:label="ifrs-full_RevenueFromInterest" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="ifrs-full_RevenueFromInterest" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_InterestExpense" xlink:label="ifrs-full_InterestExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="ifrs-full_InterestExpense" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_AmortizationOfDiscountAndTransactionCosts" xlink:label="fsm_AmortizationOfDiscountAndTransactionCosts" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="fsm_AmortizationOfDiscountAndTransactionCosts" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FeeAndCommissionExpense" xlink:label="ifrs-full_FeeAndCommissionExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="ifrs-full_FeeAndCommissionExpense" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsAccretionExpense" xlink:label="fsm_IfrsAccretionExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="fsm_IfrsAccretionExpense" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_InterestExpenseOnLeaseLiabilities" xlink:label="ifrs-full_InterestExpenseOnLeaseLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="ifrs-full_InterestExpenseOnLeaseLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_InterestAndFinanceExpenseNet" xlink:label="fsm_InterestAndFinanceExpenseNet" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="fsm_InterestAndFinanceExpenseNet" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CapitalizedInterestInProject" xlink:label="fsm_CapitalizedInterestInProject" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="fsm_CapitalizedInterestInProject" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureIncomeTaxNarrativeDetails" xlink:type="extended" xlink:title="42401 - Disclosure - INCOME TAX (Narrative) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncomeTaxesTable" xlink:label="fsm_IncomeTaxesTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasAxis" xlink:label="ifrs-full_GeographicalAreasAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="fsm_IncomeTaxesTable" xlink:to="ifrs-full_GeographicalAreasAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasDomain" xlink:label="ifrs-full_GeographicalAreasDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_GeographicalAreasAxis" xlink:to="ifrs-full_GeographicalAreasDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_CA" xlink:label="country_CA" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="country_CA" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncomeTaxesLineItems" xlink:label="fsm_IncomeTaxesLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="fsm_IncomeTaxesLineItems" xlink:to="fsm_IncomeTaxesTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ResourceRelatedExpenseAccumulatedWithNoDeferredTaxBenefitRecognized" xlink:label="fsm_ResourceRelatedExpenseAccumulatedWithNoDeferredTaxBenefitRecognized" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="fsm_IncomeTaxesLineItems" xlink:to="fsm_ResourceRelatedExpenseAccumulatedWithNoDeferredTaxBenefitRecognized" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureIncomeTaxScheduleOfDeferredTaxAssetsAndLiabilitiesDetails" xlink:type="extended" xlink:title="42404 - Disclosure - INCOME TAX (Schedule of Deferred Tax Assets and Liabilities) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" xlink:label="ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" xlink:label="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" xlink:to="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:label="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" xlink:to="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ReclamationAndClosureCostObligationMember" xlink:label="fsm_ReclamationAndClosureCostObligationMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="fsm_ReclamationAndClosureCostObligationMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UnusedTaxLossesMember" xlink:label="ifrs-full_UnusedTaxLossesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="ifrs-full_UnusedTaxLossesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_AccountsPayableAndAccruedLiabilityMember" xlink:label="fsm_AccountsPayableAndAccruedLiabilityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="fsm_AccountsPayableAndAccruedLiabilityMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DeductibilityOfResourceTaxesMember" xlink:label="fsm_DeductibilityOfResourceTaxesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="fsm_DeductibilityOfResourceTaxesMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_LeaseObligationsMember" xlink:label="fsm_LeaseObligationsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="fsm_LeaseObligationsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningPropertyMember" xlink:label="ifrs-full_MiningPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="ifrs-full_MiningPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_MiningAndForeignWithholdingTaxesMember" xlink:label="fsm_MiningAndForeignWithholdingTaxesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="fsm_MiningAndForeignWithholdingTaxesMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_EquipmentAndBuildingMember" xlink:label="fsm_EquipmentAndBuildingMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="fsm_EquipmentAndBuildingMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ConvertibleDebenturesMember" xlink:label="fsm_ConvertibleDebenturesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="fsm_ConvertibleDebenturesMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_InflationMember" xlink:label="fsm_InflationMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="fsm_InflationMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_OtherDeferredTaxLiabilitiesMember" xlink:label="fsm_OtherDeferredTaxLiabilitiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="fsm_OtherDeferredTaxLiabilitiesMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:label="ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DeferredTaxAssets" xlink:label="ifrs-full_DeferredTaxAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="ifrs-full_DeferredTaxAssets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DeferredTaxLiabilities" xlink:label="ifrs-full_DeferredTaxLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="ifrs-full_DeferredTaxLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NetDeferredTaxLiabilities" xlink:label="ifrs-full_NetDeferredTaxLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="ifrs-full_NetDeferredTaxLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DeferredTaxLiabilityAsset" xlink:label="ifrs-full_DeferredTaxLiabilityAsset" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="ifrs-full_DeferredTaxLiabilityAsset" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ReconciliationOfChangesInDeferredTaxLiabilityAssetAbstract" xlink:label="ifrs-full_ReconciliationOfChangesInDeferredTaxLiabilityAssetAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="ifrs-full_ReconciliationOfChangesInDeferredTaxLiabilityAssetAbstract" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DeferredTaxExpenseIncomeRecognisedInProfitOrLoss" xlink:label="ifrs-full_DeferredTaxExpenseIncomeRecognisedInProfitOrLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ReconciliationOfChangesInDeferredTaxLiabilityAssetAbstract" xlink:to="ifrs-full_DeferredTaxExpenseIncomeRecognisedInProfitOrLoss" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DeferredTaxRelatingToItemsChargedOrCreditedDirectlyToEquity" xlink:label="ifrs-full_DeferredTaxRelatingToItemsChargedOrCreditedDirectlyToEquity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_ReconciliationOfChangesInDeferredTaxLiabilityAssetAbstract" xlink:to="ifrs-full_DeferredTaxRelatingToItemsChargedOrCreditedDirectlyToEquity" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureIncomeTaxScheduleOfUnrecognizedDeductibleTemporaryDifferenceAndUnusedTaxLossesDetails" xlink:type="extended" xlink:title="42405 - Disclosure - INCOME TAX (Schedule of Unrecognized Deductible Temporary Difference and Unused Tax Losses) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncomeTaxesTable" xlink:label="fsm_IncomeTaxesTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasAxis" xlink:label="ifrs-full_GeographicalAreasAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="fsm_IncomeTaxesTable" xlink:to="ifrs-full_GeographicalAreasAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasDomain" xlink:label="ifrs-full_GeographicalAreasDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_GeographicalAreasAxis" xlink:to="ifrs-full_GeographicalAreasDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_MX" xlink:label="country_MX" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="country_MX" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_PE" xlink:label="country_PE" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="country_PE" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncomeTaxesLineItems" xlink:label="fsm_IncomeTaxesLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="fsm_IncomeTaxesLineItems" xlink:to="fsm_IncomeTaxesTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UnusedTaxLossesForWhichNoDeferredTaxAssetRecognised" xlink:label="ifrs-full_UnusedTaxLossesForWhichNoDeferredTaxAssetRecognised" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="fsm_IncomeTaxesLineItems" xlink:to="ifrs-full_UnusedTaxLossesForWhichNoDeferredTaxAssetRecognised" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_UnusedTaxLossesRelatedToProvisionAndOther" xlink:label="fsm_UnusedTaxLossesRelatedToProvisionAndOther" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="fsm_IncomeTaxesLineItems" xlink:to="fsm_UnusedTaxLossesRelatedToProvisionAndOther" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_UnrecognizedTaxBenefitsRelatedToMineralPropertyPlantAndEquipment" xlink:label="fsm_UnrecognizedTaxBenefitsRelatedToMineralPropertyPlantAndEquipment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="fsm_IncomeTaxesLineItems" xlink:to="fsm_UnrecognizedTaxBenefitsRelatedToMineralPropertyPlantAndEquipment" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_UnusedTaxCreditsRelatedToLeaseObligations" xlink:label="fsm_UnusedTaxCreditsRelatedToLeaseObligations" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="fsm_IncomeTaxesLineItems" xlink:to="fsm_UnusedTaxCreditsRelatedToLeaseObligations" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_UnrecognizedTaxBenefitsRelatedToDerivatives" xlink:label="fsm_UnrecognizedTaxBenefitsRelatedToDerivatives" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="fsm_IncomeTaxesLineItems" xlink:to="fsm_UnrecognizedTaxBenefitsRelatedToDerivatives" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_UnrecognizedTaxBenefitsCapitalLossCarryforwards" xlink:label="fsm_UnrecognizedTaxBenefitsCapitalLossCarryforwards" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="fsm_IncomeTaxesLineItems" xlink:to="fsm_UnrecognizedTaxBenefitsCapitalLossCarryforwards" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TemporaryDifferencesAssociatedWithInvestmentsInSubsidiariesBranchesAndAssociatesAndInterestsInJointVentures" xlink:label="ifrs-full_TemporaryDifferencesAssociatedWithInvestmentsInSubsidiariesBranchesAndAssociatesAndInterestsInJointVentures" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="fsm_IncomeTaxesLineItems" xlink:to="ifrs-full_TemporaryDifferencesAssociatedWithInvestmentsInSubsidiariesBranchesAndAssociatesAndInterestsInJointVentures" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_UnrecognizedTaxLossesDeductibleTemporaryDifferencesAndTaxCredits" xlink:label="fsm_UnrecognizedTaxLossesDeductibleTemporaryDifferencesAndTaxCredits" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="fsm_IncomeTaxesLineItems" xlink:to="fsm_UnrecognizedTaxLossesDeductibleTemporaryDifferencesAndTaxCredits" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureIncomeTaxScheduleOfTaxLossesExpiryDatesDetails" xlink:type="extended" xlink:title="42406 - Disclosure - INCOME TAX (Schedule of Tax Losses Expiry Dates) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncomeTaxesTable" xlink:label="fsm_IncomeTaxesTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasAxis" xlink:label="ifrs-full_GeographicalAreasAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="fsm_IncomeTaxesTable" xlink:to="ifrs-full_GeographicalAreasAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasDomain" xlink:label="ifrs-full_GeographicalAreasDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_GeographicalAreasAxis" xlink:to="ifrs-full_GeographicalAreasDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_CA" xlink:label="country_CA" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="country_CA" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_MX" xlink:label="country_MX" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="country_MX" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeAxis" xlink:label="ifrs-full_RangeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="fsm_IncomeTaxesTable" xlink:to="ifrs-full_RangeAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="ifrs-full_RangeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_RangeAxis" xlink:to="ifrs-full_RangeDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BottomOfRangeMember" xlink:label="ifrs-full_BottomOfRangeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_RangeDomain" xlink:to="ifrs-full_BottomOfRangeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TopOfRangeMember" xlink:label="ifrs-full_TopOfRangeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_RangeDomain" xlink:to="ifrs-full_TopOfRangeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncomeTaxesLineItems" xlink:label="fsm_IncomeTaxesLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="fsm_IncomeTaxesLineItems" xlink:to="fsm_IncomeTaxesTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ExpiryYearOfTaxLossCarryforwards" xlink:label="fsm_ExpiryYearOfTaxLossCarryforwards" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="fsm_IncomeTaxesLineItems" xlink:to="fsm_ExpiryYearOfTaxLossCarryforwards" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UnusedTaxLossesForWhichNoDeferredTaxAssetRecognised" xlink:label="ifrs-full_UnusedTaxLossesForWhichNoDeferredTaxAssetRecognised" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="fsm_IncomeTaxesLineItems" xlink:to="ifrs-full_UnusedTaxLossesForWhichNoDeferredTaxAssetRecognised" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureSegmentedInformationScheduleOfSegmentedInformationDetails" xlink:type="extended" xlink:title="42501 - Disclosure - SEGMENTED INFORMATION (Schedule of Segmented Information) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOperatingSegmentsTable" xlink:label="ifrs-full_DisclosureOfOperatingSegmentsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentsAxis" xlink:label="ifrs-full_SegmentsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsTable" xlink:to="ifrs-full_SegmentsAxis" priority="2" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentsDomain" xlink:label="ifrs-full_SegmentsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_SegmentsAxis" xlink:to="ifrs-full_SegmentsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ReportableSegmentsMember" xlink:label="ifrs-full_ReportableSegmentsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_SegmentsDomain" xlink:to="ifrs-full_ReportableSegmentsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_MansfieldReportingMember" xlink:label="fsm_MansfieldReportingMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ReportableSegmentsMember" xlink:to="fsm_MansfieldReportingMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_RoxgoldSanuSReportSegmentMember" xlink:label="fsm_RoxgoldSanuSReportSegmentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_ReportableSegmentsMember" xlink:to="fsm_RoxgoldSanuSReportSegmentMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_RoxgoldSangoSReportingSegmentMember" xlink:label="fsm_RoxgoldSangoSReportingSegmentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_ReportableSegmentsMember" xlink:to="fsm_RoxgoldSangoSReportingSegmentMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CuzcatlanReportingSegmentMember" xlink:label="fsm_CuzcatlanReportingSegmentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_ReportableSegmentsMember" xlink:to="fsm_CuzcatlanReportingSegmentMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_BateasReportingSegmentMember" xlink:label="fsm_BateasReportingSegmentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_ReportableSegmentsMember" xlink:to="fsm_BateasReportingSegmentMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CorporateSegmentMember" xlink:label="fsm_CorporateSegmentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_ReportableSegmentsMember" xlink:to="fsm_CorporateSegmentMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentConsolidationItemsAxis" xlink:label="ifrs-full_SegmentConsolidationItemsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsTable" xlink:to="ifrs-full_SegmentConsolidationItemsAxis" priority="2" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentConsolidationItemsDomain" xlink:label="ifrs-full_SegmentConsolidationItemsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_SegmentConsolidationItemsAxis" xlink:to="ifrs-full_SegmentConsolidationItemsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MaterialReconcilingItemsMember" xlink:label="ifrs-full_MaterialReconcilingItemsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_SegmentConsolidationItemsDomain" xlink:to="ifrs-full_MaterialReconcilingItemsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:label="ifrs-full_DisclosureOfOperatingSegmentsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_DisclosureOfOperatingSegmentsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Revenue" xlink:label="ifrs-full_Revenue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_Revenue" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CostOfSalesBeforeDepreciationAndDepletion" xlink:label="fsm_CostOfSalesBeforeDepreciationAndDepletion" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="fsm_CostOfSalesBeforeDepreciationAndDepletion" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DepreciationAndAmortisationExpense" xlink:label="ifrs-full_DepreciationAndAmortisationExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_DepreciationAndAmortisationExpense" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SellingGeneralAndAdministrativeExpense" xlink:label="ifrs-full_SellingGeneralAndAdministrativeExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_SellingGeneralAndAdministrativeExpense" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ImpairmentLoss" xlink:label="ifrs-full_ImpairmentLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_ImpairmentLoss" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherGainsLosses" xlink:label="ifrs-full_OtherGainsLosses" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_OtherGainsLosses" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_FinancialIncomeExpenseTotal" xlink:label="fsm_FinancialIncomeExpenseTotal" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="fsm_FinancialIncomeExpenseTotal" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProfitLossBeforeTax" xlink:label="ifrs-full_ProfitLossBeforeTax" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_ProfitLossBeforeTax" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncomeTaxExpenseContinuingOperations" xlink:label="ifrs-full_IncomeTaxExpenseContinuingOperations" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_IncomeTaxExpenseContinuingOperations" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProfitLoss" xlink:label="ifrs-full_ProfitLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_ProfitLoss" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Assets" xlink:label="ifrs-full_Assets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="12" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_Assets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Liabilities" xlink:label="ifrs-full_Liabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="13" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_Liabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PaymentsForDevelopmentProjectExpenditure" xlink:label="ifrs-full_PaymentsForDevelopmentProjectExpenditure" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="14" xlink:from="ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:to="ifrs-full_PaymentsForDevelopmentProjectExpenditure" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureFairValueMeasurementsScheduleOfFinancialAssetsAndFinancialLiabilitiesByCategoryDetails" xlink:type="extended" xlink:title="42601 - Disclosure - FAIR VALUE MEASUREMENTS (Schedule of financial assets and financial liabilities by category) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" xlink:label="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CategoriesOfFinancialAssetsAxis" xlink:label="ifrs-full_CategoriesOfFinancialAssetsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" xlink:to="ifrs-full_CategoriesOfFinancialAssetsAxis" priority="2" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CategoriesOfFinancialAssetsDomain" xlink:label="ifrs-full_CategoriesOfFinancialAssetsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_CategoriesOfFinancialAssetsAxis" xlink:to="ifrs-full_CategoriesOfFinancialAssetsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeCategoryMember" xlink:label="ifrs-full_FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeCategoryMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_CategoriesOfFinancialAssetsDomain" xlink:to="ifrs-full_FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeCategoryMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLossCategoryMember" xlink:label="ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLossCategoryMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_CategoriesOfFinancialAssetsDomain" xlink:to="ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLossCategoryMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialAssetsAtAmortisedCostCategoryMember" xlink:label="ifrs-full_FinancialAssetsAtAmortisedCostCategoryMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_CategoriesOfFinancialAssetsDomain" xlink:to="ifrs-full_FinancialAssetsAtAmortisedCostCategoryMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CategoriesOfFinancialLiabilitiesAxis" xlink:label="ifrs-full_CategoriesOfFinancialLiabilitiesAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" xlink:to="ifrs-full_CategoriesOfFinancialLiabilitiesAxis" priority="2" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CategoriesOfFinancialLiabilitiesDomain" xlink:label="ifrs-full_CategoriesOfFinancialLiabilitiesDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_CategoriesOfFinancialLiabilitiesAxis" xlink:to="ifrs-full_CategoriesOfFinancialLiabilitiesDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialLiabilitiesAtFairValueThroughProfitOrLossCategoryMember" xlink:label="ifrs-full_FinancialLiabilitiesAtFairValueThroughProfitOrLossCategoryMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_CategoriesOfFinancialLiabilitiesDomain" xlink:to="ifrs-full_FinancialLiabilitiesAtFairValueThroughProfitOrLossCategoryMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialLiabilitiesAtAmortisedCostCategoryMember" xlink:label="ifrs-full_FinancialLiabilitiesAtAmortisedCostCategoryMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_CategoriesOfFinancialLiabilitiesDomain" xlink:to="ifrs-full_FinancialLiabilitiesAtAmortisedCostCategoryMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfFinancialAssetsAxis" xlink:label="ifrs-full_ClassesOfFinancialAssetsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="3" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" xlink:to="ifrs-full_ClassesOfFinancialAssetsAxis" priority="2" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfFinancialAssetsDomain" xlink:label="ifrs-full_ClassesOfFinancialAssetsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfFinancialAssetsAxis" xlink:to="ifrs-full_ClassesOfFinancialAssetsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsCashAndCashEquivalentsMember" xlink:label="fsm_IfrsCashAndCashEquivalentsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfFinancialAssetsDomain" xlink:to="fsm_IfrsCashAndCashEquivalentsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TradeReceivablesConcentrateSalesMember" xlink:label="fsm_TradeReceivablesConcentrateSalesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_ClassesOfFinancialAssetsDomain" xlink:to="fsm_TradeReceivablesConcentrateSalesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TradeReceivablesDorSalesAssetsMember" xlink:label="fsm_TradeReceivablesDorSalesAssetsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_ClassesOfFinancialAssetsDomain" xlink:to="fsm_TradeReceivablesDorSalesAssetsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_InvestmentsInEquitySecuritiesMember" xlink:label="fsm_InvestmentsInEquitySecuritiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_ClassesOfFinancialAssetsDomain" xlink:to="fsm_InvestmentsInEquitySecuritiesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_OtherReceivablesMember" xlink:label="fsm_OtherReceivablesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_ClassesOfFinancialAssetsDomain" xlink:to="fsm_OtherReceivablesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfFinancialLiabilitiesAxis" xlink:label="ifrs-full_ClassesOfFinancialLiabilitiesAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="4" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" xlink:to="ifrs-full_ClassesOfFinancialLiabilitiesAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfFinancialLiabilitiesDomain" xlink:label="ifrs-full_ClassesOfFinancialLiabilitiesDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfFinancialLiabilitiesAxis" xlink:to="ifrs-full_ClassesOfFinancialLiabilitiesDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TradePayablesMember" xlink:label="fsm_TradePayablesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfFinancialLiabilitiesDomain" xlink:to="fsm_TradePayablesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PayrollPayableMember" xlink:label="fsm_PayrollPayableMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_ClassesOfFinancialLiabilitiesDomain" xlink:to="fsm_PayrollPayableMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ShareUnitsPayableMember" xlink:label="fsm_ShareUnitsPayableMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_ClassesOfFinancialLiabilitiesDomain" xlink:to="fsm_ShareUnitsPayableMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_MetalForwardSalesContractLiabilityMember" xlink:label="fsm_MetalForwardSalesContractLiabilityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_ClassesOfFinancialLiabilitiesDomain" xlink:to="fsm_MetalForwardSalesContractLiabilityMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CreditFacilitiesMember" xlink:label="fsm_CreditFacilitiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_ClassesOfFinancialLiabilitiesDomain" xlink:to="fsm_CreditFacilitiesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ConvertibleNotes2024Member" xlink:label="fsm_ConvertibleNotes2024Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_ClassesOfFinancialLiabilitiesDomain" xlink:to="fsm_ConvertibleNotes2024Member" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebenturesMember" xlink:label="fsm_DebenturesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_ClassesOfFinancialLiabilitiesDomain" xlink:to="fsm_DebenturesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_OtherPayablesMember" xlink:label="fsm_OtherPayablesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_ClassesOfFinancialLiabilitiesDomain" xlink:to="fsm_OtherPayablesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:label="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:to="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialAssets" xlink:label="ifrs-full_FinancialAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:to="ifrs-full_FinancialAssets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialLiabilities" xlink:label="ifrs-full_FinancialLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:to="ifrs-full_FinancialLiabilities" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureFairValueMeasurementsScheduleOfFairValuesOfFinancialAssetsAndFinancialLiabilitiesDetails" xlink:type="extended" xlink:title="42602 - Disclosure - FAIR VALUE MEASUREMENTS (Schedule of fair values of financial assets and financial liabilities) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" xlink:label="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LevelsOfFairValueHierarchyAxis" xlink:label="ifrs-full_LevelsOfFairValueHierarchyAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" xlink:to="ifrs-full_LevelsOfFairValueHierarchyAxis" priority="2" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LevelsOfFairValueHierarchyDomain" xlink:label="ifrs-full_LevelsOfFairValueHierarchyDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_LevelsOfFairValueHierarchyAxis" xlink:to="ifrs-full_LevelsOfFairValueHierarchyDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Level1OfFairValueHierarchyMember" xlink:label="ifrs-full_Level1OfFairValueHierarchyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_LevelsOfFairValueHierarchyDomain" xlink:to="ifrs-full_Level1OfFairValueHierarchyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Level2OfFairValueHierarchyMember" xlink:label="ifrs-full_Level2OfFairValueHierarchyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_LevelsOfFairValueHierarchyDomain" xlink:to="ifrs-full_Level2OfFairValueHierarchyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfFinancialAssetsAxis" xlink:label="ifrs-full_ClassesOfFinancialAssetsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" xlink:to="ifrs-full_ClassesOfFinancialAssetsAxis" priority="2" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfFinancialAssetsDomain" xlink:label="ifrs-full_ClassesOfFinancialAssetsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfFinancialAssetsAxis" xlink:to="ifrs-full_ClassesOfFinancialAssetsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TradeReceivablesConcentrateSalesMember" xlink:label="fsm_TradeReceivablesConcentrateSalesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfFinancialAssetsDomain" xlink:to="fsm_TradeReceivablesConcentrateSalesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_InvestmentsInEquitySecuritiesMember" xlink:label="fsm_InvestmentsInEquitySecuritiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_ClassesOfFinancialAssetsDomain" xlink:to="fsm_InvestmentsInEquitySecuritiesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfFinancialLiabilitiesAxis" xlink:label="ifrs-full_ClassesOfFinancialLiabilitiesAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="3" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" xlink:to="ifrs-full_ClassesOfFinancialLiabilitiesAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfFinancialLiabilitiesDomain" xlink:label="ifrs-full_ClassesOfFinancialLiabilitiesDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfFinancialLiabilitiesAxis" xlink:to="ifrs-full_ClassesOfFinancialLiabilitiesDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ShareUnitsPayableMember" xlink:label="fsm_ShareUnitsPayableMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfFinancialLiabilitiesDomain" xlink:to="fsm_ShareUnitsPayableMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_MetalForwardSalesContractLiabilityMember" xlink:label="fsm_MetalForwardSalesContractLiabilityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_ClassesOfFinancialLiabilitiesDomain" xlink:to="fsm_MetalForwardSalesContractLiabilityMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:label="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:to="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TransfersOutOfLevel1IntoLevel2OfFairValueHierarchyAssets" xlink:label="ifrs-full_TransfersOutOfLevel1IntoLevel2OfFairValueHierarchyAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:to="ifrs-full_TransfersOutOfLevel1IntoLevel2OfFairValueHierarchyAssets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TransfersOutOfLevel2IntoLevel1OfFairValueHierarchyAssets" xlink:label="ifrs-full_TransfersOutOfLevel2IntoLevel1OfFairValueHierarchyAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:to="ifrs-full_TransfersOutOfLevel2IntoLevel1OfFairValueHierarchyAssets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TransfersIntoLevel3OfFairValueHierarchyAssets" xlink:label="ifrs-full_TransfersIntoLevel3OfFairValueHierarchyAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:to="ifrs-full_TransfersIntoLevel3OfFairValueHierarchyAssets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TransfersOutOfLevel3OfFairValueHierarchyAssets" xlink:label="ifrs-full_TransfersOutOfLevel3OfFairValueHierarchyAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:to="ifrs-full_TransfersOutOfLevel3OfFairValueHierarchyAssets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TransfersOutOfLevel1IntoLevel2OfFairValueHierarchyLiabilities" xlink:label="ifrs-full_TransfersOutOfLevel1IntoLevel2OfFairValueHierarchyLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:to="ifrs-full_TransfersOutOfLevel1IntoLevel2OfFairValueHierarchyLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TransfersOutOfLevel2IntoLevel1OfFairValueHierarchyLiabilities" xlink:label="ifrs-full_TransfersOutOfLevel2IntoLevel1OfFairValueHierarchyLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:to="ifrs-full_TransfersOutOfLevel2IntoLevel1OfFairValueHierarchyLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TransfersIntoLevel3OfFairValueHierarchyLiabilities" xlink:label="ifrs-full_TransfersIntoLevel3OfFairValueHierarchyLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:to="ifrs-full_TransfersIntoLevel3OfFairValueHierarchyLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TransfersOutOfLevel3OfFairValueHierarchyLiabilities" xlink:label="ifrs-full_TransfersOutOfLevel3OfFairValueHierarchyLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:to="ifrs-full_TransfersOutOfLevel3OfFairValueHierarchyLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialAssetsAtFairValue" xlink:label="ifrs-full_FinancialAssetsAtFairValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:to="ifrs-full_FinancialAssetsAtFairValue" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialLiabilitiesAtFairValue" xlink:label="ifrs-full_FinancialLiabilitiesAtFairValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:to="ifrs-full_FinancialLiabilitiesAtFairValue" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureFairValueMeasurementsScheduleOfFinancialAssetsAndFinancialLiabilitiesNotAlreadyMeasuredAtFairValueDetails" xlink:type="extended" xlink:title="42603 - Disclosure - FAIR VALUE MEASUREMENTS (Schedule of financial assets and financial liabilities not already measured at fair value) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" xlink:label="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MeasurementAxis" xlink:label="ifrs-full_MeasurementAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" xlink:to="ifrs-full_MeasurementAxis" priority="2" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MeasurementDomain" xlink:label="ifrs-full_MeasurementDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_MeasurementAxis" xlink:to="ifrs-full_MeasurementDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NotMeasuredAtFairValueInStatementOfFinancialPositionButForWhichFairValueIsDisclosedMember" xlink:label="ifrs-full_NotMeasuredAtFairValueInStatementOfFinancialPositionButForWhichFairValueIsDisclosedMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MeasurementDomain" xlink:to="ifrs-full_NotMeasuredAtFairValueInStatementOfFinancialPositionButForWhichFairValueIsDisclosedMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfFinancialLiabilitiesAxis" xlink:label="ifrs-full_ClassesOfFinancialLiabilitiesAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" xlink:to="ifrs-full_ClassesOfFinancialLiabilitiesAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfFinancialLiabilitiesDomain" xlink:label="ifrs-full_ClassesOfFinancialLiabilitiesDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfFinancialLiabilitiesAxis" xlink:to="ifrs-full_ClassesOfFinancialLiabilitiesDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CreditFacilitiesMember" xlink:label="fsm_CreditFacilitiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfFinancialLiabilitiesDomain" xlink:to="fsm_CreditFacilitiesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ConvertibleNotes2024Member" xlink:label="fsm_ConvertibleNotes2024Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_ClassesOfFinancialLiabilitiesDomain" xlink:to="fsm_ConvertibleNotes2024Member" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebenturesMember" xlink:label="fsm_DebenturesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_ClassesOfFinancialLiabilitiesDomain" xlink:to="fsm_DebenturesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LevelsOfFairValueHierarchyAxis" xlink:label="ifrs-full_LevelsOfFairValueHierarchyAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="3" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" xlink:to="ifrs-full_LevelsOfFairValueHierarchyAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LevelsOfFairValueHierarchyDomain" xlink:label="ifrs-full_LevelsOfFairValueHierarchyDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_LevelsOfFairValueHierarchyAxis" xlink:to="ifrs-full_LevelsOfFairValueHierarchyDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Level2OfFairValueHierarchyMember" xlink:label="ifrs-full_Level2OfFairValueHierarchyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_LevelsOfFairValueHierarchyDomain" xlink:to="ifrs-full_Level2OfFairValueHierarchyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:label="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:to="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialLiabilities" xlink:label="ifrs-full_FinancialLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:to="ifrs-full_FinancialLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialLiabilitiesAtFairValue" xlink:label="ifrs-full_FinancialLiabilitiesAtFairValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="fsm_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems" xlink:to="ifrs-full_FinancialLiabilitiesAtFairValue" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureManagementOfFinancialRiskScheduleOfCompanySMaximumExposureToCreditRiskDetails" xlink:type="extended" xlink:title="42701 - Disclosure - MANAGEMENT OF FINANCIAL RISK (Schedule of Company's Maximum Exposure to Credit Risk) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:label="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfRisksAxis" xlink:label="ifrs-full_TypesOfRisksAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:to="ifrs-full_TypesOfRisksAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfRisksDomain" xlink:label="ifrs-full_TypesOfRisksDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_TypesOfRisksAxis" xlink:to="ifrs-full_TypesOfRisksDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialRiskMember" xlink:label="ifrs-full_FinancialRiskMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_TypesOfRisksDomain" xlink:to="ifrs-full_FinancialRiskMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CreditRiskMember" xlink:label="ifrs-full_CreditRiskMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_FinancialRiskMember" xlink:to="ifrs-full_CreditRiskMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:label="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashAndCashEquivalents" xlink:label="ifrs-full_CashAndCashEquivalents" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_CashAndCashEquivalents" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TradeAndOtherCurrentReceivables" xlink:label="ifrs-full_TradeAndOtherCurrentReceivables" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_TradeAndOtherCurrentReceivables" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrentTaxAssetsCurrent" xlink:label="ifrs-full_CurrentTaxAssetsCurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_CurrentTaxAssetsCurrent" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherNoncurrentReceivables" xlink:label="ifrs-full_OtherNoncurrentReceivables" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_OtherNoncurrentReceivables" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialAssets" xlink:label="ifrs-full_FinancialAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_FinancialAssets" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureManagementOfFinancialRiskScheduleOfCompanySLiquidityRiskDetails" xlink:type="extended" xlink:title="42702 - Disclosure - MANAGEMENT OF FINANCIAL RISK (Schedule of Company's Liquidity Risk) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:label="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MaturityAxis" xlink:label="ifrs-full_MaturityAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:to="ifrs-full_MaturityAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MaturityDomain" xlink:label="ifrs-full_MaturityDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_MaturityAxis" xlink:to="ifrs-full_MaturityDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NotLaterThanOneYearMember" xlink:label="ifrs-full_NotLaterThanOneYearMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MaturityDomain" xlink:to="ifrs-full_NotLaterThanOneYearMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LaterThanOneYearMember" xlink:label="ifrs-full_LaterThanOneYearMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_MaturityDomain" xlink:to="ifrs-full_LaterThanOneYearMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LaterThanOneYearAndNotLaterThanFiveYearsMember" xlink:label="ifrs-full_LaterThanOneYearAndNotLaterThanFiveYearsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_LaterThanOneYearMember" xlink:to="ifrs-full_LaterThanOneYearAndNotLaterThanFiveYearsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LaterThanOneYearAndNotLaterThanThreeYearsMember" xlink:label="ifrs-full_LaterThanOneYearAndNotLaterThanThreeYearsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_LaterThanOneYearAndNotLaterThanFiveYearsMember" xlink:to="ifrs-full_LaterThanOneYearAndNotLaterThanThreeYearsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LaterThanThreeYearsAndNotLaterThanFiveYearsMember" xlink:label="ifrs-full_LaterThanThreeYearsAndNotLaterThanFiveYearsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_LaterThanOneYearMember" xlink:to="ifrs-full_LaterThanThreeYearsAndNotLaterThanFiveYearsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LaterThanFiveYearsMember" xlink:label="ifrs-full_LaterThanFiveYearsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_LaterThanOneYearMember" xlink:to="ifrs-full_LaterThanFiveYearsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:label="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_LiquidityAmountAvailable" xlink:label="fsm_LiquidityAmountAvailable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="fsm_LiquidityAmountAvailable" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TradeAndOtherPayables" xlink:label="ifrs-full_TradeAndOtherPayables" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_TradeAndOtherPayables" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NetDebt" xlink:label="ifrs-full_NetDebt" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_NetDebt" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Provisions" xlink:label="ifrs-full_Provisions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_Provisions" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncomeTaxPayableUndiscountedCashFlows" xlink:label="fsm_IncomeTaxPayableUndiscountedCashFlows" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="fsm_IncomeTaxPayableUndiscountedCashFlows" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_UndiscountedLeaseLiability" xlink:label="fsm_UndiscountedLeaseLiability" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="fsm_UndiscountedLeaseLiability" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherLiabilities" xlink:label="ifrs-full_OtherLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_OtherLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialLiabilities" xlink:label="ifrs-full_FinancialLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_FinancialLiabilities" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureManagementOfFinancialRiskDisclosureOfNatureAndExtentArisingFromFinancialInstrumentsCurrencyRiskDetails" xlink:type="extended" xlink:title="42703 - Disclosure - MANAGEMENT OF FINANCIAL RISK (Disclosure of Nature and Extent Arising from Financial Instruments - Currency Risk) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:label="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasAxis" xlink:label="ifrs-full_GeographicalAreasAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:to="ifrs-full_GeographicalAreasAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasDomain" xlink:label="ifrs-full_GeographicalAreasDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_GeographicalAreasAxis" xlink:to="ifrs-full_GeographicalAreasDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_CA" xlink:label="country_CA" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="country_CA" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_PE" xlink:label="country_PE" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="country_PE" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_MX" xlink:label="country_MX" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="country_MX" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_AR" xlink:label="country_AR" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="country_AR" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_WestAfricaMember" xlink:label="fsm_WestAfricaMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="fsm_WestAfricaMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_AU" xlink:label="country_AU" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="country_AU" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_EuropeanUnionGeographicalAreaMember" xlink:label="fsm_EuropeanUnionGeographicalAreaMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="fsm_EuropeanUnionGeographicalAreaMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AssetsAndLiabilitiesAxis" xlink:label="ifrs-full_AssetsAndLiabilitiesAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:to="ifrs-full_AssetsAndLiabilitiesAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AssetsAndLiabilitiesDomain" xlink:label="ifrs-full_AssetsAndLiabilitiesDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_AssetsAndLiabilitiesAxis" xlink:to="ifrs-full_AssetsAndLiabilitiesDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CashEquivalentsAndCashMember" xlink:label="fsm_CashEquivalentsAndCashMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_AssetsAndLiabilitiesDomain" xlink:to="fsm_CashEquivalentsAndCashMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_MarketableSecuritiesMember" xlink:label="fsm_MarketableSecuritiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_AssetsAndLiabilitiesDomain" xlink:to="fsm_MarketableSecuritiesMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_RestrictedCashMember" xlink:label="fsm_RestrictedCashMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_AssetsAndLiabilitiesDomain" xlink:to="fsm_RestrictedCashMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TradeAndValueAddedTaxLongTermReceivableMember" xlink:label="fsm_TradeAndValueAddedTaxLongTermReceivableMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_AssetsAndLiabilitiesDomain" xlink:to="fsm_TradeAndValueAddedTaxLongTermReceivableMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncomeTaxReceivableMember" xlink:label="fsm_IncomeTaxReceivableMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_AssetsAndLiabilitiesDomain" xlink:to="fsm_IncomeTaxReceivableMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ValueAddedTaxLongTermReceivableMember" xlink:label="fsm_ValueAddedTaxLongTermReceivableMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_AssetsAndLiabilitiesDomain" xlink:to="fsm_ValueAddedTaxLongTermReceivableMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TradeAndOtherPayablesMember" xlink:label="fsm_TradeAndOtherPayablesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_AssetsAndLiabilitiesDomain" xlink:to="fsm_TradeAndOtherPayablesMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ProvisionsCurrentMember" xlink:label="fsm_ProvisionsCurrentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_AssetsAndLiabilitiesDomain" xlink:to="fsm_ProvisionsCurrentMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncomeTaxPayableMember" xlink:label="fsm_IncomeTaxPayableMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_AssetsAndLiabilitiesDomain" xlink:to="fsm_IncomeTaxPayableMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_LiabilitiesOtherMember" xlink:label="fsm_LiabilitiesOtherMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="ifrs-full_AssetsAndLiabilitiesDomain" xlink:to="fsm_LiabilitiesOtherMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ProvisionsNoncurrentMember" xlink:label="fsm_ProvisionsNoncurrentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="ifrs-full_AssetsAndLiabilitiesDomain" xlink:to="fsm_ProvisionsNoncurrentMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:label="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ForeignExposureOnAssetLiabilitiesNet" xlink:label="fsm_ForeignExposureOnAssetLiabilitiesNet" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="fsm_ForeignExposureOnAssetLiabilitiesNet" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PercentageChangeEffectOnForeignDenominatedItemsAmount" xlink:label="fsm_PercentageChangeEffectOnForeignDenominatedItemsAmount" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="fsm_PercentageChangeEffectOnForeignDenominatedItemsAmount" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PercentageChangeOnForeignDenominatedItemsPercentage" xlink:label="fsm_PercentageChangeOnForeignDenominatedItemsPercentage" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="fsm_PercentageChangeOnForeignDenominatedItemsPercentage" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureManagementOfFinancialRiskDisclosureOfNatureAndExtentArisingFromFinancialInstrumentsCommodityPriceRiskDetails" xlink:type="extended" xlink:title="42704 - Disclosure - MANAGEMENT OF FINANCIAL RISK (Disclosure of Nature and Extent Arising from Financial Instruments - Commodity Price Risk) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:label="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TypeOfCommodityAxis" xlink:label="fsm_TypeOfCommodityAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:to="fsm_TypeOfCommodityAxis" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TypeOfCommodityMember" xlink:label="fsm_TypeOfCommodityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="fsm_TypeOfCommodityAxis" xlink:to="fsm_TypeOfCommodityMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_SilverCommodityTypeMember" xlink:label="fsm_SilverCommodityTypeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="fsm_TypeOfCommodityMember" xlink:to="fsm_SilverCommodityTypeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_GoldCommodityTypeMember" xlink:label="fsm_GoldCommodityTypeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="fsm_TypeOfCommodityMember" xlink:to="fsm_GoldCommodityTypeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_LeadCommodityMember" xlink:label="fsm_LeadCommodityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="fsm_TypeOfCommodityMember" xlink:to="fsm_LeadCommodityMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ZincCommodityMember" xlink:label="fsm_ZincCommodityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="fsm_TypeOfCommodityMember" xlink:to="fsm_ZincCommodityMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:label="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PercentagePriceChangeEffectOnSalesAmount" xlink:label="fsm_PercentagePriceChangeEffectOnSalesAmount" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="fsm_PercentagePriceChangeEffectOnSalesAmount" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PercentageChangeOnCommodityPricePercentage" xlink:label="fsm_PercentageChangeOnCommodityPricePercentage" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="fsm_PercentageChangeOnCommodityPricePercentage" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncreaseDecreaseInSalesDueToPriceChangesOfCommodity" xlink:label="fsm_IncreaseDecreaseInSalesDueToPriceChangesOfCommodity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="fsm_IncreaseDecreaseInSalesDueToPriceChangesOfCommodity" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IfrsLineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="fsm_IfrsLineOfCreditFacilityMaximumBorrowingCapacity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="fsm_IfrsLineOfCreditFacilityMaximumBorrowingCapacity" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureSupplementalCashFlowInformationScheduleOfChangesInLiabilitiesArisingFromFinancingActivitiesDetails" xlink:type="extended" xlink:title="42802 - Disclosure - SUPPLEMENTAL CASH FLOW INFORMATION (Schedule of changes in liabilities arising from financing activities) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable" xlink:label="ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesArisingFromFinancingActivitiesAxis" xlink:label="ifrs-full_LiabilitiesArisingFromFinancingActivitiesAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable" xlink:to="ifrs-full_LiabilitiesArisingFromFinancingActivitiesAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesArisingFromFinancingActivitiesDomain" xlink:label="ifrs-full_LiabilitiesArisingFromFinancingActivitiesDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_LiabilitiesArisingFromFinancingActivitiesAxis" xlink:to="ifrs-full_LiabilitiesArisingFromFinancingActivitiesDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DebentureMember" xlink:label="fsm_DebentureMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_LiabilitiesArisingFromFinancingActivitiesDomain" xlink:to="fsm_DebentureMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ConvertibleNotes2024Member" xlink:label="fsm_ConvertibleNotes2024Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_LiabilitiesArisingFromFinancingActivitiesDomain" xlink:to="fsm_ConvertibleNotes2024Member" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LeaseLiabilitiesMember" xlink:label="ifrs-full_LeaseLiabilitiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_LiabilitiesArisingFromFinancingActivitiesDomain" xlink:to="ifrs-full_LeaseLiabilitiesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TermCreditFacilityMember" xlink:label="fsm_TermCreditFacilityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_LiabilitiesArisingFromFinancingActivitiesDomain" xlink:to="fsm_TermCreditFacilityMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:label="ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesArisingFromFinancingActivities" xlink:label="ifrs-full_LiabilitiesArisingFromFinancingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="ifrs-full_LiabilitiesArisingFromFinancingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncreaseInLiabilitiesArisingFromVariousFinancingActivities" xlink:label="fsm_IncreaseInLiabilitiesArisingFromVariousFinancingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="fsm_IncreaseInLiabilitiesArisingFromVariousFinancingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PaymentOfTransactionCost" xlink:label="fsm_PaymentOfTransactionCost" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="fsm_PaymentOfTransactionCost" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DecreaseInLiabilitiesArisingFromFinancingActivitiesDueToAllocatedToEquity" xlink:label="fsm_DecreaseInLiabilitiesArisingFromFinancingActivitiesDueToAllocatedToEquity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="fsm_DecreaseInLiabilitiesArisingFromFinancingActivitiesDueToAllocatedToEquity" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncreaseInLiabilitiesArisingFromFinancingActivitiesDueToTransactionCostsAllocatedToEquity" xlink:label="fsm_IncreaseInLiabilitiesArisingFromFinancingActivitiesDueToTransactionCostsAllocatedToEquity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="fsm_IncreaseInLiabilitiesArisingFromFinancingActivitiesDueToTransactionCostsAllocatedToEquity" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DecreaseThroughTerminations" xlink:label="fsm_DecreaseThroughTerminations" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="fsm_DecreaseThroughTerminations" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncreaseDecreaseRelatedToConversionOfDebentures" xlink:label="fsm_IncreaseDecreaseRelatedToConversionOfDebentures" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="fsm_IncreaseDecreaseRelatedToConversionOfDebentures" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncreaseDecreaseThroughInterest" xlink:label="fsm_IncreaseDecreaseThroughInterest" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="fsm_IncreaseDecreaseThroughInterest" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncreaseDecreaseInLiabilitiesArisingFromFinancingActivitiesDueToExtinguishment" xlink:label="fsm_IncreaseDecreaseInLiabilitiesArisingFromFinancingActivitiesDueToExtinguishment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="fsm_IncreaseDecreaseInLiabilitiesArisingFromFinancingActivitiesDueToExtinguishment" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DecreaseThroughPrincipalPayments" xlink:label="fsm_DecreaseThroughPrincipalPayments" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="fsm_DecreaseThroughPrincipalPayments" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncreaseDecreaseThroughChangesInForeignExchangeLiabilitiesArisingFromFinancingActivities" xlink:label="fsm_IncreaseDecreaseThroughChangesInForeignExchangeLiabilitiesArisingFromFinancingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="12" xlink:from="ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="fsm_IncreaseDecreaseThroughChangesInForeignExchangeLiabilitiesArisingFromFinancingActivities" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureNonControllingInterestsDetails" xlink:type="extended" xlink:title="42901 - Disclosure - NON-CONTROLLING INTERESTS (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_StatementOfChangesInEquityTable" xlink:label="ifrs-full_StatementOfChangesInEquityTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_StatementOfChangesInEquityTable" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningAssetsMember" xlink:label="ifrs-full_MiningAssetsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_MiningAssetsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningPropertyMember" xlink:label="ifrs-full_MiningPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningAssetsMember" xlink:to="ifrs-full_MiningPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_YaramokoMeasuredAndIndicatedPropertyMember" xlink:label="fsm_YaramokoMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_YaramokoMeasuredAndIndicatedPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_SeguelaMeasuredAndIndicatedPropertyMember" xlink:label="fsm_SeguelaMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_SeguelaMeasuredAndIndicatedPropertyMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityAxis" xlink:label="ifrs-full_ComponentsOfEquityAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="ifrs-full_StatementOfChangesInEquityTable" xlink:to="ifrs-full_ComponentsOfEquityAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ifrs-full_ComponentsOfEquityDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ComponentsOfEquityAxis" xlink:to="ifrs-full_ComponentsOfEquityDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncontrollingInterestsMember" xlink:label="ifrs-full_NoncontrollingInterestsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ComponentsOfEquityDomain" xlink:to="ifrs-full_NoncontrollingInterestsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_GovernmentOfBurkinaFasoMember" xlink:label="fsm_GovernmentOfBurkinaFasoMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_NoncontrollingInterestsMember" xlink:to="fsm_GovernmentOfBurkinaFasoMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_GovernmentOfCteDivoireMember" xlink:label="fsm_GovernmentOfCteDivoireMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_NoncontrollingInterestsMember" xlink:to="fsm_GovernmentOfCteDivoireMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_StatementOfChangesInEquityLineItems" xlink:label="ifrs-full_StatementOfChangesInEquityLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_StatementOfChangesInEquityTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProportionOfOwnershipInterestsHeldByNoncontrollingInterests" xlink:label="ifrs-full_ProportionOfOwnershipInterestsHeldByNoncontrollingInterests" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_ProportionOfOwnershipInterestsHeldByNoncontrollingInterests" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncontrollingInterests" xlink:label="ifrs-full_NoncontrollingInterests" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_NoncontrollingInterests" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProfitLossAttributableToNoncontrollingInterests" xlink:label="ifrs-full_ProfitLossAttributableToNoncontrollingInterests" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_ProfitLossAttributableToNoncontrollingInterests" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureNonControllingInterestsSummarizedFinancialStatementsDetails" xlink:type="extended" xlink:title="42902 - Disclosure - NON-CONTROLLING INTERESTS - Summarized Financial Statements (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_StatementOfChangesInEquityTable" xlink:label="ifrs-full_StatementOfChangesInEquityTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_StatementOfChangesInEquityTable" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningAssetsMember" xlink:label="ifrs-full_MiningAssetsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_MiningAssetsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningPropertyMember" xlink:label="ifrs-full_MiningPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningAssetsMember" xlink:to="ifrs-full_MiningPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_YaramokoMeasuredAndIndicatedPropertyMember" xlink:label="fsm_YaramokoMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_YaramokoMeasuredAndIndicatedPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_SeguelaMeasuredAndIndicatedPropertyMember" xlink:label="fsm_SeguelaMeasuredAndIndicatedPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_SeguelaMeasuredAndIndicatedPropertyMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityAxis" xlink:label="ifrs-full_ComponentsOfEquityAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="ifrs-full_StatementOfChangesInEquityTable" xlink:to="ifrs-full_ComponentsOfEquityAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ifrs-full_ComponentsOfEquityDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ComponentsOfEquityAxis" xlink:to="ifrs-full_ComponentsOfEquityDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncontrollingInterestsMember" xlink:label="ifrs-full_NoncontrollingInterestsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ComponentsOfEquityDomain" xlink:to="ifrs-full_NoncontrollingInterestsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_GovernmentOfBurkinaFasoMember" xlink:label="fsm_GovernmentOfBurkinaFasoMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_NoncontrollingInterestsMember" xlink:to="fsm_GovernmentOfBurkinaFasoMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_GovernmentOfCteDivoireMember" xlink:label="fsm_GovernmentOfCteDivoireMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_NoncontrollingInterestsMember" xlink:to="fsm_GovernmentOfCteDivoireMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_StatementOfChangesInEquityLineItems" xlink:label="ifrs-full_StatementOfChangesInEquityLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_StatementOfChangesInEquityTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProportionOfOwnershipInterestsHeldByNoncontrollingInterests" xlink:label="ifrs-full_ProportionOfOwnershipInterestsHeldByNoncontrollingInterests" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_ProportionOfOwnershipInterestsHeldByNoncontrollingInterests" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrentAssets" xlink:label="ifrs-full_CurrentAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_CurrentAssets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncurrentAssets" xlink:label="ifrs-full_NoncurrentAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_NoncurrentAssets" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrentLiabilities" xlink:label="ifrs-full_CurrentLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_CurrentLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncurrentLiabilities" xlink:label="ifrs-full_NoncurrentLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_NoncurrentLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NetAssetsLiabilities" xlink:label="ifrs-full_NetAssetsLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_NetAssetsLiabilities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncontrollingInterests" xlink:label="ifrs-full_NoncontrollingInterests" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_NoncontrollingInterests" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_NonControllingIncomeStatementAbstract" xlink:label="fsm_NonControllingIncomeStatementAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="fsm_NonControllingIncomeStatementAbstract" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Revenue" xlink:label="ifrs-full_Revenue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="fsm_NonControllingIncomeStatementAbstract" xlink:to="ifrs-full_Revenue" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComprehensiveIncome" xlink:label="ifrs-full_ComprehensiveIncome" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="fsm_NonControllingIncomeStatementAbstract" xlink:to="ifrs-full_ComprehensiveIncome" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_StatementOfCashFlowsAbstract" xlink:label="ifrs-full_StatementOfCashFlowsAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_StatementOfCashFlowsAbstract" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashFlowsFromUsedInOperatingActivities" xlink:label="ifrs-full_CashFlowsFromUsedInOperatingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_StatementOfCashFlowsAbstract" xlink:to="ifrs-full_CashFlowsFromUsedInOperatingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashFlowsFromUsedInInvestingActivities" xlink:label="ifrs-full_CashFlowsFromUsedInInvestingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_StatementOfCashFlowsAbstract" xlink:to="ifrs-full_CashFlowsFromUsedInInvestingActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashFlowsFromUsedInFinancingActivities" xlink:label="ifrs-full_CashFlowsFromUsedInFinancingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_StatementOfCashFlowsAbstract" xlink:to="ifrs-full_CashFlowsFromUsedInFinancingActivities" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureContingenciesAndCapitalCommitmentsNarrativeDetails" xlink:type="extended" xlink:title="43001 - Disclosure - CONTINGENCIES AND CAPITAL COMMITMENTS (Narrative) (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOtherProvisionsTable" xlink:label="ifrs-full_DisclosureOfOtherProvisionsTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfOtherProvisionsTable" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningAssetsMember" xlink:label="ifrs-full_MiningAssetsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="ifrs-full_MiningAssetsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MiningPropertyMember" xlink:label="ifrs-full_MiningPropertyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningAssetsMember" xlink:to="ifrs-full_MiningPropertyMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CayllomaMineMember" xlink:label="fsm_CayllomaMineMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_MiningPropertyMember" xlink:to="fsm_CayllomaMineMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasAxis" xlink:label="ifrs-full_GeographicalAreasAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="ifrs-full_DisclosureOfOtherProvisionsTable" xlink:to="ifrs-full_GeographicalAreasAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasDomain" xlink:label="ifrs-full_GeographicalAreasDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_GeographicalAreasAxis" xlink:to="ifrs-full_GeographicalAreasDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_PE" xlink:label="country_PE" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="country_PE" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_CI" xlink:label="country_CI" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_GeographicalAreasDomain" xlink:to="country_CI" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfContingentLiabilitiesAxis" xlink:label="ifrs-full_ClassesOfContingentLiabilitiesAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="3" xlink:from="ifrs-full_DisclosureOfOtherProvisionsTable" xlink:to="ifrs-full_ClassesOfContingentLiabilitiesAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfContingentLiabilitiesDomain" xlink:label="ifrs-full_ClassesOfContingentLiabilitiesDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ClassesOfContingentLiabilitiesAxis" xlink:to="ifrs-full_ClassesOfContingentLiabilitiesDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CivilWorkMember" xlink:label="fsm_CivilWorkMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ClassesOfContingentLiabilitiesDomain" xlink:to="fsm_CivilWorkMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" xlink:label="ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="4" xlink:from="ifrs-full_DisclosureOfOtherProvisionsTable" xlink:to="ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" xlink:label="ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" xlink:to="ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_EnteringIntoSignificantCommitmentsOrContingentLiabilitiesMember" xlink:label="ifrs-full_EnteringIntoSignificantCommitmentsOrContingentLiabilitiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" xlink:to="ifrs-full_EnteringIntoSignificantCommitmentsOrContingentLiabilitiesMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PeriodOfTaxAssessmentAxis" xlink:label="fsm_PeriodOfTaxAssessmentAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="5" xlink:from="ifrs-full_DisclosureOfOtherProvisionsTable" xlink:to="fsm_PeriodOfTaxAssessmentAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PeriodOfTaxAssessmentDomain" xlink:label="fsm_PeriodOfTaxAssessmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="fsm_PeriodOfTaxAssessmentAxis" xlink:to="fsm_PeriodOfTaxAssessmentDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_RelatedToTaxPeriodOneMember" xlink:label="fsm_RelatedToTaxPeriodOneMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="fsm_PeriodOfTaxAssessmentDomain" xlink:to="fsm_RelatedToTaxPeriodOneMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_RelatedToTaxPeriodTwoMember" xlink:label="fsm_RelatedToTaxPeriodTwoMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="fsm_PeriodOfTaxAssessmentDomain" xlink:to="fsm_RelatedToTaxPeriodTwoMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityAxis" xlink:label="ifrs-full_ComponentsOfEquityAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="6" xlink:from="ifrs-full_DisclosureOfOtherProvisionsTable" xlink:to="ifrs-full_ComponentsOfEquityAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ifrs-full_ComponentsOfEquityDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_ComponentsOfEquityAxis" xlink:to="ifrs-full_ComponentsOfEquityDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncontrollingInterestsMember" xlink:label="ifrs-full_NoncontrollingInterestsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_ComponentsOfEquityDomain" xlink:to="ifrs-full_NoncontrollingInterestsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_GovernmentOfCteDivoireMember" xlink:label="fsm_GovernmentOfCteDivoireMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_NoncontrollingInterestsMember" xlink:to="fsm_GovernmentOfCteDivoireMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:label="ifrs-full_DisclosureOfOtherProvisionsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="ifrs-full_DisclosureOfOtherProvisionsTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_UndiscountedClosureCosts" xlink:label="fsm_UndiscountedClosureCosts" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="fsm_UndiscountedClosureCosts" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_ProgressiveClosureActivities" xlink:label="fsm_ProgressiveClosureActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="fsm_ProgressiveClosureActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PostClosureActivities" xlink:label="fsm_PostClosureActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="fsm_PostClosureActivities" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_GuaranteesWithGovernmentCurrentYear" xlink:label="fsm_GuaranteesWithGovernmentCurrentYear" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="fsm_GuaranteesWithGovernmentCurrentYear" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CapitalCommitments" xlink:label="ifrs-full_CapitalCommitments" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="ifrs-full_CapitalCommitments" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PotentialEarlyTerminationPaymentAmount" xlink:label="fsm_PotentialEarlyTerminationPaymentAmount" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="fsm_PotentialEarlyTerminationPaymentAmount" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_EarlyTerminationPaymentAmountOutstanding" xlink:label="fsm_EarlyTerminationPaymentAmountOutstanding" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="fsm_EarlyTerminationPaymentAmountOutstanding" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PaymentOfLitigationSettlement" xlink:label="fsm_PaymentOfLitigationSettlement" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="fsm_PaymentOfLitigationSettlement" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_IncomeTaxInterestAndPenalties" xlink:label="fsm_IncomeTaxInterestAndPenalties" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:to="fsm_IncomeTaxInterestAndPenalties" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureImpairmentNarrativeDetails" xlink:type="extended" xlink:title="43101 - Disclosure - IMPAIRMENT - Narrative (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedTable" xlink:label="ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IndividualAssetsOrCashgeneratingUnitsAxis" xlink:label="ifrs-full_IndividualAssetsOrCashgeneratingUnitsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedTable" xlink:to="ifrs-full_IndividualAssetsOrCashgeneratingUnitsAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IndividualAssetsOrCashgeneratingUnitsDomain" xlink:label="ifrs-full_IndividualAssetsOrCashgeneratingUnitsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_IndividualAssetsOrCashgeneratingUnitsAxis" xlink:to="ifrs-full_IndividualAssetsOrCashgeneratingUnitsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_LinderoCashGeneratingUnitMember" xlink:label="fsm_LinderoCashGeneratingUnitMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_IndividualAssetsOrCashgeneratingUnitsDomain" xlink:to="fsm_LinderoCashGeneratingUnitMember" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_SanJoseCashGeneratingUnitMember" xlink:label="fsm_SanJoseCashGeneratingUnitMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_IndividualAssetsOrCashgeneratingUnitsDomain" xlink:to="fsm_SanJoseCashGeneratingUnitMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeAxis" xlink:label="ifrs-full_RangeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedTable" xlink:to="ifrs-full_RangeAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="ifrs-full_RangeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_RangeAxis" xlink:to="ifrs-full_RangeDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BottomOfRangeMember" xlink:label="ifrs-full_BottomOfRangeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_RangeDomain" xlink:to="ifrs-full_BottomOfRangeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TopOfRangeMember" xlink:label="ifrs-full_TopOfRangeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_RangeDomain" xlink:to="ifrs-full_TopOfRangeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedLineItems" xlink:label="ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedLineItems" xlink:to="ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DescriptionOfDiscountRatesAppliedToCashFlowProjections" xlink:label="ifrs-full_DescriptionOfDiscountRatesAppliedToCashFlowProjections" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedLineItems" xlink:to="ifrs-full_DescriptionOfDiscountRatesAppliedToCashFlowProjections" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CommodityDiscountRateBenchmarkPercentage" xlink:label="fsm_CommodityDiscountRateBenchmarkPercentage" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedLineItems" xlink:to="fsm_CommodityDiscountRateBenchmarkPercentage" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CommodityPriceAmountRelatedToCommodityDiscountRateBenchmark" xlink:label="fsm_CommodityPriceAmountRelatedToCommodityDiscountRateBenchmark" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedLineItems" xlink:to="fsm_CommodityPriceAmountRelatedToCommodityDiscountRateBenchmark" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CommodityPriceUsedForDeterminingFairValueAssumptionsLongTerm" xlink:label="fsm_CommodityPriceUsedForDeterminingFairValueAssumptionsLongTerm" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedLineItems" xlink:to="fsm_CommodityPriceUsedForDeterminingFairValueAssumptionsLongTerm" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CommodityPricePerOunceBenchmarkAmount" xlink:label="fsm_CommodityPricePerOunceBenchmarkAmount" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedLineItems" xlink:to="fsm_CommodityPricePerOunceBenchmarkAmount" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_CommodityPriceAmountRelatedToCommodityPerOunceBenchmark" xlink:label="fsm_CommodityPriceAmountRelatedToCommodityPerOunceBenchmark" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedLineItems" xlink:to="fsm_CommodityPriceAmountRelatedToCommodityPerOunceBenchmark" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ReversalOfImpairmentLoss" xlink:label="ifrs-full_ReversalOfImpairmentLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedLineItems" xlink:to="ifrs-full_ReversalOfImpairmentLoss" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ImpairmentLoss" xlink:label="ifrs-full_ImpairmentLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedLineItems" xlink:to="ifrs-full_ImpairmentLoss" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.fortunasilver.com/role/DisclosureSubsequentEventsDetails" xlink:type="extended" xlink:title="43201 - Disclosure - SUBSEQUENT EVENTS (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:label="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodTable" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" xlink:label="ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:to="ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" xlink:label="ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" xlink:to="ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisposalOfMajorSubsidiaryMember" xlink:label="ifrs-full_DisposalOfMajorSubsidiaryMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" xlink:to="ifrs-full_DisposalOfMajorSubsidiaryMember" use="optional" />
    <loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:label="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_PercentageOfInterestDisposed" xlink:label="fsm_PercentageOfInterestDisposed" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="fsm_PercentageOfInterestDisposed" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisposalGroupTotalConsideration" xlink:label="fsm_DisposalGroupTotalConsideration" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="fsm_DisposalGroupTotalConsideration" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisposalGroupConsiderationReceivableOnClosing" xlink:label="fsm_DisposalGroupConsiderationReceivableOnClosing" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="fsm_DisposalGroupConsiderationReceivableOnClosing" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisposalGroupReceivableAggregateRemaining" xlink:label="fsm_DisposalGroupReceivableAggregateRemaining" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="fsm_DisposalGroupReceivableAggregateRemaining" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisposalGroupRemainingConsiderationReceivableTerm" xlink:label="fsm_DisposalGroupRemainingConsiderationReceivableTerm" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="fsm_DisposalGroupRemainingConsiderationReceivableTerm" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_DisposalGroupMaximumContingentConsideration" xlink:label="fsm_DisposalGroupMaximumContingentConsideration" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="fsm_DisposalGroupMaximumContingentConsideration" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_NetSmelterReturnRoyaltyPercentage" xlink:label="fsm_NetSmelterReturnRoyaltyPercentage" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="fsm_NetSmelterReturnRoyaltyPercentage" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="tmb-20241231.xsd#fsm_TermOfNetSmelterReturnRoyalty" xlink:label="fsm_TermOfNetSmelterReturnRoyalty" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="fsm_TermOfNetSmelterReturnRoyalty" priority="1" use="optional" />
  </definitionLink>
</link:linkbase>
