Piano teacher penning short letter (4)

I believe the answer is:

note

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

'short letter' is the definition.
(I know that short letter can be written as note)

'piano teacher penning' is the wordplay.
'NOTE' is hidden within the letters.
However, I'm uncertain how the hidden word is indicated.

Can you help me to learn more?

(Other definitions for note that I've seen before include "Cash" , "Memo; pay attention to" , "Mark - sound - money" , "Tenner, for example" , "A flat, for example" .)

I've seen this clue in The Sun.

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.