general ledger vs account book

general ledger and account book both are nouns.

Word	Noun	Adjective	Verb	Adverb
general ledger	Yes	No	No	No
account book	Yes	No	No	No

As nouns, account book is a hypernym of general ledger; that is, account book is a word with a broader meaning than general ledger:

general ledger: the ledger that contains all of the financial accounts of a business; contains offsetting debit and credit accounts (including control accounts)
account book: a record in which commercial accounts are recorded

Other hypernyms of general ledger include book, book of account, ledger, leger.

general ledger (noun)	account book (noun)
the ledger that contains all of the financial accounts of a business; contains offsetting debit and credit accounts (including control accounts)	a record in which commercial accounts are recorded