Note exposed billet-doux as work of fiction (9)
I believe the answer is:
novelette
'work of fiction' is the definition.
'novelette' can be an answer for 'fiction' (novelette is a kind of fiction). I'm unsure of the 'work of' bit.
'note exposed billet-doux' is the wordplay.
'note' becomes 'n' (abbreviation).
'exposed' means to look at the middle letters (outside letters removed).
'billet doux' becomes 'loveletter' ('love letter' can be a synonym of 'billet doux').
The middle of 'loveletter' is 'ovelette'.
'n'+'ovelette'='NOVELETTE'
'as' is the link.
Can you help me to learn more?
(Other definitions for novelette that I've seen before include "Short and light tale" , "Short book of fiction" , "romance?" , "Short story" , "Short work of fiction" .)