/ Dictionary / Index M munnion: Meaning and Definition of Find definitions for: mun•nion Pronunciation: (mun'yun), [key] — n. a mullion or muntin. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Munkácsy Muñoz Marín Related Content Daily Word Quiz: longevity Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language