/ Dictionary / Index B birretta: Meaning and Definition of Find definitions for: bir•ret•ta Pronunciation: (bu-ret'u), [key] — n. biretta. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: birretta (Thesaurus) birr birrus Related Content Daily Word Quiz: grimace Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language