/ Dictionary / Index M monoacid: Meaning and Definition of Find definitions for: mon•o•ac•id Pronunciation: (mon"ō-as'id, mon'ō-as"id), [key] — Chem. Chem. —adj. —n. an acid having one replaceable hydrogen atom. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. monoacetin monoalphabetic substitution Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language