Synonyms for arch

arc, curve, vault, dome, cupola, ogive, span, bend, archivolt, squinch, architrave, arching, archway, curvature, bend, cove, camber.

Arches include: round, horseshoe, lancet, ogee, trefoil, basket-handle, decorated, Tudor, Egyptian, Gothic, Ionian, flat, Roman.

extend, round, stretch, camber, curve, bend, form, shape, hunch, hump, hook, arch over.

Antonyms straighten*, unbend, smooth.