Generalization and Specialization
Generalization - Identification and partitioning of the common properties
of real-world entities or abstractions. Generalization is the process
used in design of object models.
Specialization is adding additional attributes and behaviors to a common core
of attributes an behavior. Specialization is a frequent mode of
evolution of existing object structures. Specialization should be used
Generalization and Specialization are two modes of realizing inheritance