--- title: MetafieldDefinitionIdentifierInput - GraphQL Admin description: The input fields that identify metafield definitions. api_version: 2025-10 api_name: admin type: input-object api_type: graphql source_url: html: https://shopify.dev/docs/api/admin-graphql/latest/input-objects/metafielddefinitionidentifierinput md: https://shopify.dev/docs/api/admin-graphql/latest/input-objects/metafielddefinitionidentifierinput.md --- # Metafield​Definition​Identifier​Input input\_object The input fields that identify metafield definitions. ## Fields * key [String!](https://shopify.dev/docs/api/admin-graphql/latest/scalars/String) non-null The unique identifier for the metafield definition within its namespace. * namespace [String](https://shopify.dev/docs/api/admin-graphql/latest/scalars/String) The container for a group of metafields that the metafield definition will be associated with. If omitted, the app-reserved namespace will be used. * owner​Type [Metafield​Owner​Type!](https://shopify.dev/docs/api/admin-graphql/latest/enums/MetafieldOwnerType) non-null The resource type that the metafield definition is attached to. *** ## Map No referencing types