: the greatest height at which an airplane can fly properly
: the height above the ground of the bottom of the lowest layer of clouds
: an upper limit <a ceiling on prices>
Word History of CEILING
As we now line a coat with a lining, we also used to ceil a room with a ceiling. The verb ceil, however, is now very seldom used on its own. Originally to ceil was to cover the surfaces of a room—both above and on the sides—with a coating of plaster or with carved panels. Ceiling could once mean nearly the same as “paneling,” but the only sense we now use refers only to what is overhead in a room.