Classical dancing (6)
I believe the answer is:
ballet
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">classical dancing</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ballet that I've seen before include "old madrigal" , "Theatrical entertainment" , "The Nutcracker or Giselle, say" , "Artistic dance form" , "Dance entertainment" .)