/ Dictionary / Index A antiatom: Meaning and Definition of Find definitions for: an•ti•at•om Pronunciation: (an'tē-at"um, an'tī-), [key] — n. Physics. an atom of antimatter. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. antiart antiauxin Related Content Daily Word Quiz: eccentric Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language