ceiling.- n. inner top of a room or building. eg. The lamp hangs from the ceiling.
roof.- n. outer top of a room or building. eg. After the rins they had to sweep the tree leaves from the roof .
floor.- n. 1. inner bottom part of room or building. 2. one of several stories in which a building might be divided. eg. The rug on the wooden floor is imported from China.
ground.- n. the bottom part of everything, where one sets foot on. eg. The sailors were glad to arrive to safe ground finally.
