/ Dictionary / Index M M.S.W.: Meaning and Definition of Find definitions for: M.S.W. Pronunciation: [key] Master of Social Welfare. Master of Social Work or Master in Social Work. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. MSTS MT Related Content Daily Word Quiz: winsome Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language