/ Dictionary / Index F frustum: Meaning and Definition of Find definitions for: frus•tum Pronunciation: (frus'tum), [key] — pl. -tums, -ta the part of a conical solid left after cutting off a top portion with a plane parallel to the base. 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. See also: frustum (Thesaurus) frustulum frutescent Related Content Daily Word Quiz: clairvoyant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language