The term 'STEP IN 'SWAN LAKE'' is a reference to the famous ballet composed by Pyotr Ilyich Tchaikovsky. The crossword solution for this term is PAS, which stands for 'PAS de deux, ' a French phrase meaning 'dance for two.' PAS de deux is a type of dance in which two dancers perform a duet, often with intricate and synchronized movements. In the ballet Swan Lake, the PAS de deux is performed by the lead characters, Odette and Prince Siegfried.