Raised in the middle (6)
I believe the answer is:
arched
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">raised in the middle</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 arched that I've seen before include "bow" , "Curved up in the centre" , "Bent" , "Raised in the centre" , "Curved (over an opening)" .)