Pronunciation: (frus'tum), [key]
—pl. -tums, -taPronunciation: (-tu). [key] Geom.
1. the part of a conical solid left after cutting off a top portion with a plane parallel to the base.
2. the part of a solid, as a cone or pyramid, between two usually parallel cutting planes.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.