/ Dictionary / Index N N.M.U.: Meaning and Definition of Find definitions for: N.M.U. Pronunciation: [key] National Maritime Union. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. NMSS NNE Related Content Daily Word Quiz: soporific Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language