Definition from Wiktionary, the free dictionary
ceiling (plural ceilings)
- The surface that bounds the upper limit of a room.
- the dining room had an ornate ceiling
- The upper limit of an object or action.
- price ceilings
- (aviation) The highest altitude at which an aircraft may fly.
- (mathematics) The smallest integer greater than or equal to a given number.
- the ceiling of 4.5 is 5, the ceiling of -4.5 is -4
Derived terms 
Terms derived from ceiling
upper limit of room
- Present participle of ceil.