/ Dictionary / Index M M.S.N.: Meaning and Definition of Find definitions for: M.S.N. Pronunciation: [key] Master of Science in Nursing. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. M.S.Mgt.E. M.S.P.E. Related Content Daily Word Quiz: eureka Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language