/ Dictionary / Index M mother of vinegar: Meaning and Definition of Find definitions for: moth'er of vin'egar Pronunciation: [key] mother. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mother-of-thyme mother's boy Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language