What does 책해 mean?
책 means book
책 is a noun, and simply means "book".
책 + 이 indicates it is the subject of the sentence.
If you really did mean asking about 책하다, you can find it in a series of idioms or a few other meanings, such as "denounce, bring sth to account, etc".
It's not a term. If you tried to translate it, it means "doing the book"