Hole (for a coin?) (4)
I believe the answer is:
slot
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">hole for a coin?</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 slot that I've seen before include "Long narrow aperture" , "Long narrow slit" , "Narrow opening, for cash say" , "Opening for coin or TV programme" , "Long narrow opening" .)