Big dance (4)
I believe the answer is:
prom
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">big dance</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 prom that I've seen before include "Formal dance at the end of school year" , "Concert - school dance (US)" , "Henry Wood concert" , "Seaside walk (abbr.)" , "Classical music concert for which part of the audience stands" .)