/ Dictionary / Index M Mason jar: Meaning and Definition of Find definitions for: Ma'son jar" Pronunciation: [key] a glass jar with a wide mouth and an airtight screw top, much used in home canning. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Masonite masonry Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language