a hard substance such as wood, stone, or metal that is put on the outside of a structure, especially a building, to protect it or make it look more attractive 包层;(尤指建筑物的)覆面,镀层
a layer of plastic material that is built into the bottom of the walls of a building to stop damp from rising up into the walls from the ground (建筑物墙底的)防潮层