Elevation of inaugural location for Black King's castle (6)
I believe the answer is:
height
'elevation' is the definition.
(height is a kind of elevation)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for height that I've seen before include "Measurement from base to top" , "Measurement from top to bottom" , "Hill, elevation" , "Stature" , "size up?" .)