Degree of bending (9)
I believe the answer is:
curvature
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">degree of bending</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for curvature that I've seen before include "Degree of bending" , "Continual bending" , "Bend" .)