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