Vent or aperture (7)
I believe the answer is:
orifice
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">vent</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">aperture</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for orifice that I've seen before include "Vent" , "Hole in the head, perhaps?" , "Hole, opening" , "provided by gold and diamonds" , "For CIE, I look for an opening" .)