Set of twenty (5)
I believe the answer is:
score
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">set of twenty</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 score that I've seen before include "Tally; scratch" , "musical work" , "Orchestrate; twenty" , "Chalk up - twenty" , "Gain a point (20 of them?)" .)