/ Dictionary / Index F frat: Meaning and Definition of Find definitions for: frat Pronunciation: (frat), [key] — n. Informal. fraternity (def. 1). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: frat (Thesaurus) frass fratch 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