sackbut (săkˈbət) [key], Renaissance name for the slide trombone, probably derived from the old French word sacqueboute, which means "pull-push." The instrument achieved its present form in the 15th cent., the only differences being a narrower bore and a smaller bell. These differences lent the sackbut, sometimes called a posuane, a less mellow tone than its modern counterpart.
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