> ## Documentation Index > Fetch the complete documentation index at: https://docs.metriport.com/llms.txt > Use this file to discover all available pages before exploring further. # StructureDefinition > A definition of a FHIR structure. This resource is used to describe the underlying resources, data types defined in FHIR, and also for describing extensions and constraints on resources and data types. ## Properties | Name | Required | Type | Description | | ------------------- | -------- | ---------------------------------------------------------------------- | ------------------------------------------------------------------------------------------ | | url | Yes | uri | Canonical identifier for this structure definition, represented as a URI (globally unique) | | identifier | No | [Identifier](/medical-api/fhir/data-types/identifier)\[] | Additional identifier for the structure definition | | version | No | string | Business version of the structure definition | | name | Yes | string | Name for this structure definition (computer friendly) | | title | No | string | Name for this structure definition (human friendly) | | status | Yes | code | draft / active / retired / unknown | | experimental | No | boolean | For testing purposes, not real usage | | date | No | dateTime | Date last changed | | publisher | No | string | Name of the publisher (organization or individual) | | contact | No | [ContactDetail](/medical-api/fhir/data-types/contactdetail)\[] | Contact details for the publisher | | description | No | markdown | Natural language description of the structure definition | | useContext | No | [UsageContext](/medical-api/fhir/data-types/usagecontext)\[] | The context that the content is intended to support | | jurisdiction | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept)\[] | Intended jurisdiction for structure definition (if applicable) | | purpose | No | markdown | Why this structure definition is defined | | copyright | No | markdown | Use and/or publishing restrictions | | keyword | No | [Coding](/medical-api/fhir/data-types/coding)\[] | Assist with indexing and finding | | fhirVersion | No | code | FHIR Version this StructureDefinition targets | | mapping | No | StructureDefinitionMapping | External specification that the content is mapped to | | - id | No | string | Unique id for inter-element referencing | | - extension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Additional content defined by implementations | | - modifierExtension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Extensions that cannot be ignored even if unrecognized | | - identity | Yes | id | Internal id when this mapping is used | | - uri | No | uri | Identifies what this mapping refers to | | - name | No | string | Names what this mapping refers to | | - comment | No | string | Versions, Issues, Scope limitations etc. | | kind | Yes | code | primitive-type / complex-type / resource / logical | | abstract | Yes | boolean | Whether the structure is abstract | | context | No | StructureDefinitionContext | If an extension, where it can be used in instances | | - id | No | string | Unique id for inter-element referencing | | - extension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Additional content defined by implementations | | - modifierExtension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Extensions that cannot be ignored even if unrecognized | | - type | Yes | code | fhirpath / element / extension | | - expression | Yes | string | Where the extension can be used in instances | | contextInvariant | No | string\[] | FHIRPath invariants - when the extension can be used | | type | Yes | uri | Type defined or constrained by this structure | | baseDefinition | No | canonical | Definition that this type is constrained/specialized from | | derivation | No | code | specialization / constraint - How relates to base definition | | snapshot | No | StructureDefinitionSnapshot | Snapshot view of the structure | | - id | No | string | Unique id for inter-element referencing | | - extension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Additional content defined by implementations | | - modifierExtension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Extensions that cannot be ignored even if unrecognized | | - element | Yes | [ElementDefinition](/medical-api/fhir/data-types/elementdefinition)\[] | Definition of elements in the resource (if no StructureDefinition) | | differential | No | StructureDefinitionDifferential | Differential view of the structure | | - id | No | string | Unique id for inter-element referencing | | - extension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Additional content defined by implementations | | - modifierExtension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Extensions that cannot be ignored even if unrecognized | | - element | Yes | [ElementDefinition](/medical-api/fhir/data-types/elementdefinition)\[] | Definition of elements in the resource (if no StructureDefinition) | ## Search Parameters | Name | Type | Description | Expression | | --------------------- | --------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------- | | context | token | A use context assigned to the structure definition | StructureDefinition.useContext.value | | context-quantity | quantity | A quantity- or range-valued use context assigned to the structure definition | StructureDefinition.useContext.value | | context-type | token | A type of use context assigned to the structure definition | StructureDefinition.useContext.code | | date | date | The structure definition publication date | StructureDefinition.date | | description | string | The description of the structure definition | StructureDefinition.description | | jurisdiction | token | Intended jurisdiction for the structure definition | StructureDefinition.jurisdiction | | name | string | Computationally friendly name of the structure definition | StructureDefinition.name | | publisher | string | Name of the publisher of the structure definition | StructureDefinition.publisher | | status | token | The current status of the structure definition | StructureDefinition.status | | title | string | The human-friendly name of the structure definition | StructureDefinition.title | | url | uri | The uri that identifies the structure definition | StructureDefinition.url | | version | token | The business version of the structure definition | StructureDefinition.version | | context-type-quantity | composite | A use context type and quantity- or range-based value assigned to the structure definition | StructureDefinition.useContext | | context-type-value | composite | A use context type and value assigned to the structure definition | StructureDefinition.useContext | | identifier | token | External identifier for the structure definition | StructureDefinition.identifier | | abstract | token | Whether the structure is abstract | StructureDefinition.abstract | | base | reference | Definition that this type is constrained/specialized from | StructureDefinition.baseDefinition | | base-path | token | Path that identifies the base element | StructureDefinition.snapshot.element.base.path | | derivation | token | specialization / constraint - How relates to base definition | StructureDefinition.derivation | | experimental | token | For testing purposes, not real usage | StructureDefinition.experimental | | ext-context | token | The system is the URL for the context-type: e.g. [http://hl7.org/fhir/extension-context-type#element/CodeableConcept.text](http://hl7.org/fhir/extension-context-type#element/CodeableConcept.text) | StructureDefinition.context.type | | keyword | token | A code for the StructureDefinition | StructureDefinition.keyword | | kind | token | primitive-type / complex-type / resource / logical | StructureDefinition.kind | | path | token | A path that is constrained in the StructureDefinition | StructureDefinition.snapshot.element.path | | type | uri | Type defined or constrained by this structure | StructureDefinition.type | | valueset | reference | A vocabulary binding reference | StructureDefinition.snapshot.element.binding.valueSet | ## Inherited Properties | Name | Required | Type | Description | | ----------------- | -------- | ------------------------------------------------------ | ------------------------------------------------------ | | id | No | string | Logical id of this artifact | | meta | No | [Meta](/medical-api/fhir/data-types/meta) | Metadata about the resource | | implicitRules | No | uri | A set of rules under which this content was created | | language | No | code | Language of the resource content | | text | No | [Narrative](/medical-api/fhir/data-types/narrative) | Text summary of the resource, for human interpretation | | contained | No | Resource\[] | Contained, inline Resources | | extension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Additional content defined by implementations | | modifierExtension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Extensions that cannot be ignored | To view the FHIR specification for this resource, see [StructureDefinition](https://www.hl7.org/fhir/StructureDefinition/StructureDefinition).