/ Dictionary / Index M mouth organ: Meaning and Definition of Find definitions for: mouth' or"gan Pronunciation: [key] harmonica (def. 1). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mouth harp mouthpart Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language