n. The act or process of specializing; a making or fixing of special differences or requirements; differentiation.n. The state of being or becoming specialized; a condition of fixed or developed differentiation, as of parts, organs, or individuals, with reference to form, appearance, function, etc.n. In biology, that evolutionary process whereby parts or organs primitively indifferent or of common character become differentiated in form or function (usually in both); also, the result of such process or course of development; adaptive modification.n. Also spelled specialisation.