a frame typically composed of a horizontal bar or beam rigidly joined or fitted at each end to the top of a transverse A-frame, used as a barrier, a transverse support for planking, etc.; horse.

Civil Engineering .

one of a number of bents, having sloping sides of framework or piling, for supporting the deck or stringers of a bridge.

a bridge made of these.

noun

beam , brace , framework , horse , sawhorse , stand , support