See bitter has been spilled in the word-book (8)

I believe the answer is:

libretto

I'm a little stuck... Click here to teach me more about this clue!

'book' is the definition.
(I know that libretto is a type of book)

I don't understand the remainder of the clue.

(Other definitions for libretto that I've seen before include "textbook" , "11 down book" , "The words of an opera or musical play" , "component of opera" , "text for musicians" .)

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.