Swan Lake or The Nutcracker, say (6)
I believe the answer is:
ballet
I believe this clue is a double definition.
'swan lake' is the first definition.
(I've seen this in another clue)
'the nutcracker say' is the second definition.
(I know that The Nutcracker is a ballet)
(Other definitions for ballet that I've seen before include "The Nutcracker or Giselle, say" , "Type of dance" , "Artistic dance form" , "Nureyev's forte" , "eg Giselle" .)