flying buttress

Two flying buttresses on the abbey of Bath, England.

flying buttress, masonry structure typically consisting of an inclined bar carried on a half arch that extends (“flies”) from the upper part of a wall to a pier some distance away and carries the thrust of a roof or vault. A pinnacle (vertical ornament of pyramidal or conical shape) often crowns the pier, adding weight and enhancing stability. The flying buttress evolved in the Gothic era from earlier simpler, hidden supports. The design increased the supporting power of the buttress and allowed for the creation of the high-ceilinged churches typical of Gothic architecture.