scheme in Dutch

A systematic plan of future action. [from 18th c.]

(mathematics) A mathematical structure that generalizes the notion of an algebraic variety in several ways, such as taking account of multiplicities and allowing "varieties" defined over any commutative ring. Formally, a locally ringed space that admits a covering by open sets, each of which is isomorphic to an affine scheme (i.e. the spectrum of some commutative ring).