Part of a joint (5)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">part of a joint</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 tenon that I've seen before include "Projection used in a mortise joint" , "Mortise extension" , "Wood fitting into a mortise" , "Tongue of wood for joint" , "Kind of saw" .)