/ Dictionary / Index F frustule: Meaning and Definition of Find definitions for: frus•tule Pronunciation: (frus'chl), [key] — n. Bot. the siliceous cell wall of a diatom. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. frustration frustulum Related Content Daily Word Quiz: nonchalant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language