specialization
/ˌspɛʃəlɪˈzeɪʃn̩/
The act or process of specializing.
The area in which someone specializes.
The adaptation of an organism to a specific environment, or adaptation of an organ to a particular function.
A proof, axiom, problem, or definition whose cases are completely covered by another, broader concept.
A triangle is a specialization of a polygon to one with exactly three sides.