Part of a tree (6)
I believe the answer is:
branch
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">part of a tree</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 branch that I've seen before include "Part of organisation or tree" , "local office" , "'Fork, offshoot (6)'" , "Fork of a main stem" , "part of a big organisation" .)