Short for numerically effective; introduced by Miles Reid.
Meanings
(not-comparable) Of a line bundle on a complete algebraic variety over a field: such that the degree of its restriction to every algebraic curve in the variety is non-negative.
[…] this condition is the numerical consequence of the condition that for some mgt;0, the linear system #124;mD#124; is effective and free; thus nef = "numerically (effective and free)". 1983, Miles Reid, “Minimal Models of Canonical 3-Folds”, in Advanced Studies in Pure Mathematics, volume 1, page 131: