Hide note inside some yarn (5)
I believe the answer is:
skein
'some yarn' is the definition.
(skein can mean a length of yarn)
'hide note inside' is the wordplay.
'hide' becomes 'sk' (I can't explain this - if you can you should believe this answer much more).
'note' becomes 'e' (musical note).
'inside' becomes 'in'.
'sk'+'e'+'in'='SKEIN'
Can you help me to learn more?
(Other definitions for skein that I've seen before include "Clock face" , "Hank" , "Coil of wool - flock of geese" , "Loosely coiled bundle of wool" , "flock in flight" .)