Area of damaged tissue (6)
I believe the answer is:
lesion
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">area of damaged tissue</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 lesion that I've seen before include "Injury to living tissue" , "Abrasion" , "Harmful change in bodily tissue as from injury" , "A cut or wound in insole" , "Kind of injury in insole" .)