Check mark (4)
I believe the answer is:
tick
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">check mark</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 tick that I've seen before include "Clock's sound" , "Arrangement for deferred payment" , "Instant - credit" , "Make sound like old clock" , "Credit (sl.)" .)