/ Dictionary / Index M MG: Meaning and Definition of Find definitions for: MG Pronunciation: [key] machine gun. major general. military government. myasthenia gravis. Mg Pronunciation: [key] left hand. Mg Pronunciation: [key] magnesium. mg Pronunciation: [key] milligram; milligrams. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mg (Thesaurus) M.F.T. mGal Related Content Daily Word Quiz: placid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language