(Architecture)the almost triangular space between one side of the outer curve of an arch, a wall, and the ceiling or framework (建筑)拱肩 ■the space between the shoulders of adjoining arches and the ceiling or moulding above 拱门下的三角形空间
语源
late Middle English: perhaps from Anglo-Norman French spaund(e)re, or from espaundre 'expand'