Very small, we note (3)
I believe the answer is:
wee
'very small' is the definition.
('wee' is a Scottish word for small)
'we note' is the wordplay.
'note' becomes 'e' (musical note).
'we'+'e'='WEE'
(Other definitions for wee that I've seen before include "Informally tiny as in Scotland" , "number one" , "Small, like Willy Winkie" , "It's small in Scotland" , "Jimmy" .)