A saw-horse or sawhorse (saw-buck, trestle, buck) is a beam with four legs used to support a board or plank for sawing. A pair of sawhorses can support a plank, forming a scaffold. In certain circles, it is also known as a "mule" and a short sawhorse is known as a pony. The names come from the shape of the frame, which resembles a horse. A sawhorse may also be a rack for supporting logs for sawing, known in the US as a sawbuck.