(n.) A square or oblong opening in a deck or floor, affording passage from one deck or story to another; the entrance to a cellar.
Thesaurus Entries
French door, apse, arcade, arcature, arch, arched roof, back door, barway, bulkhead, camber, carriage entrance, ceilinged roof, cellar door, cellarway, concameration, concha, cove, cupola, dome, door, doorjamb, doorpost, doorway, front door, gate, gatepost, gateway, geodesic dome, hatch, hatchway, igloo, keystone, lintel, ogive, porch, portal, porte cochere, postern, propylaeum, pylon, scuttle, side door, skewback, span, stile, storm door, threshold, tollgate, trap, trap door, turnpike, turnstile, vault, vaulting, voussoir
