Definitions
1.nounThe overhead closure of a room."the dining room had an ornate ceiling"
2.nounThe upper limit of an object or action.
3.nounThe highest altitude at which an aircraft can safely maintain flight.
4.nounThe measurement of visible distance from ground or sea level to an overcast cloud cover; under a clear sky, the ceiling measurement is identified as "unlimited."
5.nounThe smallest integer greater than or equal to a given number."the ceiling of 4.5 is 5, the ceiling of -4.5 is -4"
6.nounThe inner planking of a vessel.