roof
noun
a protective covering that covers or forms the top of a building
protective covering on top of a motor vehicle
the inner top surface of a covered area or hollow space
“the roof of the cave was very high”
“I could see the roof of the bear's mouth”
an upper limit on what is allowed
“he put a ceiling on the number of women who worked for him”
“there was a roof on salaries”
verb
provide a building with a roof; cover a building with a roof
Source: WordNet 3.1, Princeton University