/ Dictionary / Index M MRA: Meaning and Definition of Find definitions for: MRA Pronunciation: [key] Moral Re-Armament. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. MR M-radiation Related Content Daily Word Quiz: dissonant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language