Definition of roof :
1. That which resembles, or corresponds to, the covering or the ceiling of a house; as, the roof of a cavern; the roof of the mouth.
2. The cover of any building, including the roofing ( see Roofing) and all the materials and construction necessary to carry and maintain the same upon the walls or other uprights. In the case of a building with vaulted ceilings protected by an outer roof, some writers call the vault the roof, and the outer protection the roof mask. It is better, however, to consider the vault as the ceiling only, in cases where it has farther covering.
3. The surface or bed of rock immediately overlying a bed of coal or a flat vein.
4. To cover with a roof.
5. To inclose in a house; figuratively, to shelter.
cover, gambrel, flat, house, awning, detonator, hip, jacket, hood, spire, cupola, break, crownwork, housetop, tent, apex, dome, home, capital, dormer-windowed, ceiling, mansard, jerkinhead, penthouse, pyramidal, French, shelter, jacket crown, high, height, detonating device, pileus, habitation, vertex, chapiter
top (part of speech: noun)