Anything in Grakn, whether a type or an instance of data, is a Concept. The diagram below, illustrates how the Concept Superclass is inherited by its direct and indirect descendants.
Type refers to a Concept Type as defined in the schema.
Thing refers to an instance of data that is an instantiation of a Concept Type.
Rule refers to a Graql Rule.
The methods called on Concepts are bound to the [transaction](/docs/client-api/overview#transaction) that was used to retrieve the concept initially. As soon as the transaction in question is closed, methods can no longer be called on the retrieved Concepts. To do so, we must retrieve the Concept again with a newly created transaction.
In the sections that follow, we learn about the methods available on Concept, Type, EntityType, AttributeType, RelationshipType, Thing, Attribute, Relationship and Rule.