/ Dictionary / Index A antacid: Meaning and Definition of Find definitions for: ant•ac•id Pronunciation: (ant-as'id), [key] — adj. preventing, neutralizing, or counteracting acidity, as of the stomach. —n. an antacid agent. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: antacid (Thesaurus) Antabuse Antaeus Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language