A class that cannot be directly instantiated (Booch et al. 2005). Compare concrete class.
A data type that is defined by the operations that manipulate it and thus has its representation details hidden.
A specification that defines the external view of the information hiding class—that is, all the information required by the user of the class.
An operation that is declared in an abstract class but not implemented.
A computation that executes as a result of a state transition.
See concurrent object:.
A computation that executes for the duration of a state.
An outside user or related set of users who interact with the system ...