ceiling in WordNet English dictionary

1. 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"; "they established a cap for prices"
   ceiling  roof  cap 
   
2. the overhead upper surface of a covered space
   "he hated painting the ceiling"
   ceiling 
   
3. (meteorology) altitude of the lowest layer of clouds
   ceiling 
   
4. maximum altitude at which a plane can fly (under specified conditions)
   ceiling