A short musical overture (5)

I believe the answer is:

intro

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

'overture' is the definition.
(I've seen this before)

I cannot understand how the rest of the clue works.

(Other definitions for intro that I've seen before include "Launch" , "Musical opening" , "Opening notes" , "First part of a news story (abbr)" , "Opening section" .)

I've seen this clue in The Globe and Mail.

Want a hint initially instead of a full solution? Install my app