/ Dictionary / Index M mRNA: Meaning and Definition of Find definitions for: mRNA Pronunciation: [key] messenger RNA. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mrna (Thesaurus) mridanga Mr. Nice Guy Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language