
The ceiling of sickbay aboard Voyager
The ceiling was the uppermost surface of a room.
In 2268, James T. Kirk offered to fill Elaan's quarters from floor to ceiling with breakable objects to allow her to expend her anger. The Elasian declined. (TOS: "Elaan of Troyius")
In 2371, a lungless Neelix told The Doctor that USS Voyager's ceiling was "hideous" and suggested that he put a tapestry or a painting there. Later, he expressed his fear that he would lie in sickbay for the rest of his life staring at the ceiling. (VOY: "Phage")