Breadcrumb Home > Dictionary > Index S sackbut: Meaning and Definition of Find definitions for: sack•but Pronunciation: (sak'but"), [key] — n. a medieval form of the trombone. an ancient stringed musical instrument. Dan. 3. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: sackbut (Thesaurus) sack sackcloth ✖ Related Content Daily Word Quiz: careening Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language