Name (of a book) (5)
I believe the answer is:
title
'name of a book' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for title that I've seen before include "Name, honorific" , "Lord, sir, doctor etc." , "established claim to ownership" , "Caption; name" , "Appellation signifying status or function" .)