On top of or higher than (5)
I believe the answer is:
above
I believe this is a double definition.
'on top of' is the first definition.
(I've seen this before)
'higher than' is the second definition.
(I've seen this in another clue)
(Other definitions for above that I've seen before include "Position of the heavens!" , "In preference to" , "Overhead" , "On top of" , "At a higher level" .)