“Buc, a buske, plated (pleated) bodie or other quilted thing worne to make or keepe the bodie straight” (1611, Cotgrave). Occasionally, in the 18th and 19th centuries, it meant to dress, deck with clothing.
However, the usual meaning of the word was the stiffened front of a bodice; the busk being a flat length of bone, whalebone, wood or, in the 17th century, sometimes horn, attached to the front of a bodice or the stays to render it inflexible. In the 18th century the busk was sometimes carved with emblems and worn pushed down into a busk sheath in front of the bodice. By the 19th and early 20th centuries stay busks were often of steel.