Relating to part of the small intestine (5)
I believe the answer is:
ileac
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">relating to part of the small intestine</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ileac that I've seen before include "of tube in body" , "Relating to the small intestine" , "part of gut" , "concerned with part of intestine" , "gutsy" .)