/ Dictionary / Index M MAO: Meaning and Definition of Find definitions for: MAO Pronunciation: [key] monoamine oxidase. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mao (Thesaurus) Manzù Mao Dun Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language