Hill; elevation (6)
I believe the answer is:
height
I believe this is a double definition.
'hill' is the first definition.
(height can mean a hill or higher ground)
'elevation' is the second definition.
(I know that elevation can be written as height)
(Other definitions for height that I've seen before include "Loftiness" , "Vertical extension" , "Hill, elevation" , "Peak" , "Rising ground; extreme example" .)