in optics, a privation or diminution of light, by the interposition of any opake body; or it is a plane where the light is either altogether obstructed, or greatly weakened, by the interposition of some opake body between it and the luminary.

in painting, an imitation of a real shadow, effected by gradually heightening and darkening the colours of such figures as by their dispositions cannot receive any direct rays from the luminary that is supposed to enlighten the piece.

SHAFT of a column, in building, is the body thereof between the base and capital: so called from its straightness.