Coin aperture (4)
I believe the answer is:
slot
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">coin aperture</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for slot that I've seen before include "This gaming machine operates by insertion of coin" , "Lots (anag.)" , "Space for coin or programme" , "Opening for coin or TV programme" , "Space for inserting coin" .)