Deer's horn (6)
I believe the answer is:
antler
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">deer's horn</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for antler that I've seen before include "Deer-horn" , "Branch" , "Stag horn" , "Branched animal horn" , "Deer's branching horn" .)