An InstanceDeclarationis an Object, Variableor Methodthat references a ModellingRulewith a HasModellingRule Referenceand is the TargetNodeof a hierarchical Referencefrom a TypeDefinitionNodeor another InstanceDeclaration. There shall be no two TypeDefinitionNodesreferencing the same InstanceDeclarationwith a hierarchical Reference, either directly or from another InstanceDeclarationof that TypeDefinitionNode, i.e. an InstanceDeclarationbelongs to exactly one TypeDefinitionNode.

The type of an InstanceDeclarationmay be abstract, however the instance must be of a concrete type.