Prom or ball
I believe the answer is:
dance
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">prom</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >'<span class="explanation-format__original">ball</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(ball can mean an event for dancing)</span><br/ ><br/ ></span>
(Other definitions for dance that I've seen before include "Jig, say" , "Eg, perform ballet" , "Fling" , "Eg, tango, waltz" , "Flamenco, perhaps" .)