/ Dictionary / Index M mainstay: Meaning and Definition of Find definitions for: main•stay Pronunciation: (mān'stā"), [key] — n. the stay that secures the mainmast forward. a person or thing that acts as a chief support or part: Coffee is the mainstay of the country's economy. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mainstay (Thesaurus) mainspring main stem Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language