nef

An extravagant table ornament and container used in the Middle Ages and Renaissance, made in the shape of a ship.

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)".