ceilings

noun

1. 1

   The overhead closure of a room.

   “the dining room had an ornate ceiling”

2. 2

   The upper limit of an object or action.

3. 3

   The highest altitude at which an aircraft can safely maintain flight.

4. 4

   The 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. 5

   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”

6. 6

   The inner planking of a vessel.