Skin, dermis (5)
I believe the answer is:
cutis
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">skin</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >'<span class="explanation-format__original">dermis</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ ></span>
(Other definitions for cutis that I've seen before include "Surface area" , "a bit skinny" , "Technical name for skin" , "skin, technically" , "Skin, dermis" .)