quasi-projective

Etymology
, the sense being that projective varieties are closed subsets of projective space while quasi-projective varieties are only required to be locally closed, a strictly weaker condition. The second, scheme-theoretic sense generalizes the first.

Adjective

 * 1)  Locally closed with respect to the Zariski topology on projective n-space; isomorphic to such a set.
 * 2)  Comprising an open subscheme of a projective scheme