/ Dictionary / Index M monoamine oxidase: Meaning and Definition of Find definitions for: mon'oamine' ox'idase Pronunciation: [key] a copper-containing enzyme that catalyzes the breakdown of monoamines. Abbr.: MAO Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. monoamine monoamine oxidase inhibitor 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