The external covering at the top of a building.

• The top outer surface of a vehicle or structure.

The upper interior surface of a cavity or space.

• Especially the roof of the mouth, a cave, or a tunnel.

Geology/mining: the rock layer immediately over a seam or vein.

• Climbing: an overhanging rock wall like a ceiling.

To cover or furnish with a roof.

• To shelter or house as if under a roof.