Curvature hard to miss in cavern (6)
I believe the answer is:
camber
'cavern' is the definition.
The answer and definition can be both natural objects as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for camber that I've seen before include "Curvature of aircraft wing" , "Curve given to surface as of road" , "may appear on road" , "bend in road" , "Slight convexity, like the surface of a road" .)