/ Dictionary / Index F frustulum: Meaning and Definition of Find definitions for: frus•tu•lum Pronunciation: (frus'tu-lum, -chu-), [key] — pl. -la a small breakfast permitted on fast days. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. frustule frustum 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