Frustum definitions

Webster's 1828 Dictionary

FRUS'TUM, n. [L. See Frustrate.] a piece or part of a solid body separated from the rest. The frustum of a cone, is the part that remains after the top is cut off by a plane parallel to the base; called otherwise a truncated cone.

WordNet (r) 3.0 (2005)

n
1: a truncated cone or pyramid; the part that is left when a cone or pyramid is cut by a plane parallel to the base and the apical part is removed

Merriam Webster's

noun (plural frustums or frusta) Etymology: New Latin, from Latin, piece, bit — more at bruise Date: 1658 the basal part of a solid cone or pyramid formed by cutting off the top by a plane parallel to the base; also the part of a solid intersected between two usually parallel planes

Oxford Reference Dictionary

n. (pl. frusta or frustums) Geom. 1 the remainder of a cone or pyramid whose upper part has been cut off by a plane parallel to its base. 2 the part of a cone or pyramid intercepted between two planes. Etymology: L, = piece cut off

Webster's 1913 Dictionary

Frustum Frus"tum, n.; pl. L. Frusta, E. Frustums. [L. fruslum piece, bit.] 1. (Geom.) The part of a solid next the base, formed by cutting off the, top; or the part of any solid, as of a cone, pyramid, etc., between two planes, which may be either parallel or inclined to each other. 2. (Arch.) One of the drums of the shaft of a column.