The external covering at the top of a building.

• The top outer surface of a vehicle or structure.

建筑物顶部的外部覆盖物。

• 车辆或结构的顶面外层。

The upper interior surface of a cavity or space.

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

腔体或空间的内部上表面。

• 尤指口腔的上壁、洞穴或隧道的顶面。

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

• Climbing: an overhanging rock wall like a ceiling.

地质/采矿：紧贴煤层或矿脉之上的岩层。

• 攀岩：像天花板一样外突的悬岩。

To cover or furnish with a roof.

• To shelter or house as if under a roof.

覆盖或安装屋顶。

• 提供庇护，如同置于屋顶之下。