Concept B is a specialization of concept A if and only if:

• every instance of concept B is also an instance of concept A; and
• there are instances of concept A which are not instances of concept B.

For instance, 'Bird' is a specialization of 'Animal' because every bird is an animal, and there are animals which are not birds (dogs, for instance).

In logic, specialization occurs when you take a statement such as:

"All cars are red"

And use it to derive statements such as:

"My car is red"

"Fred's car is red"

Specialization is an important way to generate propositional knowledge, by applying general knowledge, such as the theory of gravity , to specific instances, such as "when I release this apple, it will fall to the floor".

Generalization is the opposite of specialization

See also: Specialization (functional), Cell specialization