/ Dictionary / Index D diatomaceous: Meaning and Definition of Find definitions for: di•a•to•ma•ceous Pronunciation: (dī"u-tu-mā'shus), [key] — adj. consisting of or containing diatoms or their fossil remains. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. diatom diatomaceous earth Related Content Daily Word Quiz: portent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language