re·stric·tion / riˈstrikshən/ • n. (often restrictions) a limiting condition or measure, esp. a legal one: planning restrictions on commercial development. ∎  the limitation or control of someone or something, or the state of being limited or restricted: the restriction of local government power.DERIVATIVES: re·stric·tion·ism / -ˌnizəm/ n.re·stric·tion·ist / -nist/ adj. & n.

restriction of a relation R or function f. A relation or function obtained by restricting the domain of R or f. If “is the son of” is a relation defined on all the males in a certain country, a restriction would be this same relation defined on the males of a particular city.

restriction The cleavage of double-stranded DNA by a restriction endonuclease.