A musical character to have on the staff (4)

I believe the answer is:

clef

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

'a musical character' is the definition.
(I've seen this before)

I can't explain the remainder of the clue.

(Other definitions for clef that I've seen before include "that's marking the pitch" , "Mark determining musical pitch of notes" , "Treble or bass sign?" , "Symbol in musical score showing pitch of the notes" , "Item of musical notation" .)

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

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.