A big one to note? (3)
I believe the answer is:
toe
'a big one' is the definition.
Both the answer and definition are adjectives. Perhaps there's an association between them I don't understand?
'to note?' is the wordplay.
'note?' becomes 'e' (musical note**).
'to'+'e'='TOE'
Can you help me to learn more?
(Other definitions for toe that I've seen before include "Pedal digit" , "Conform-...the line" , "compliantly put on line" , "low digit" , "Digit on foot" .)