/ Dictionary / Index M milk of magnesia: Meaning and Definition of Find definitions for: milk' of magne'sia Pronunciation: [key] a milky white suspension in water of magnesium hydroxide, Mg (OH), used as an antacid or laxative. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. milk of almonds milk powder Related Content Daily Word Quiz: deleterious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language