Belonging to the thing (3)
I believe the answer is:
its
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">belonging to the thing</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 its that I've seen before include "Sit (anag.)" , "Belonging to something nonhuman" , "The thing's" , "Neuter possessive pronoun" , "Belonging to a particular thing" .)