passbook vs bankbook

passbook and bankbook both are nouns.

Word	Noun	Adjective	Verb	Adverb
passbook	Yes	No	No	No
bankbook	Yes	No	No	No

As nouns, passbook and bankbook are synonyms defined as:

passbook and bankbook: a record of deposits and withdrawals and interest held by depositors at certain banks

passbook (noun)	bankbook (noun)
a record of deposits and withdrawals and interest held by depositors at certain banks	a record of deposits and withdrawals and interest held by depositors at certain banks