Height, elevation (8)
I believe the answer is:
altitude
I believe this clue is a double definition.
'height' is the first definition.
(synonyms)
'elevation' is the second definition.
(I know that altitude is a type of elevation)
(Other definitions for altitude that I've seen before include "Loftiness" , "Elevation above sea-level" , "Angular distance above the horizon" , "Elevation above sea level" , "Height above sea level" .)