Part of a pen (3)
I believe the answer is:
nib
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">part of a pen</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 nib that I've seen before include "Writing point of old pen" , "Pen's point" , "Point of an old-fashioned pen" , "Pen-point" , "Pen end" .)