Show in which Calvin takes an amusing part (7)

I believe the answer is:

musical

I'm a little stuck... Click here to teach me more about this clue!

'show' is the definition.
(I know that show can be written as musical)

I don't understand the rest of the clue.

(Other definitions for musical that I've seen before include "Cats maybe" , "eg Chicago" , "Show, with numbers" , "Eg, Cats or Evita" , "Rent for one" .)

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.