bankbook vs passbook

bankbook and passbook both are nouns.

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

As nouns, bankbook and passbook are synonyms defined as:

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

bankbook (noun)	passbook (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