Alias Sol, note (3)
I believe the answer is:
soh
'note' is the definition.
(I've seen this before)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for soh that I've seen before include "Musical note; sounds like very good" , "Note of major scale" , "It's between fah and la" , "element of scale" , "It comes between fah and lah" .)