credit card in a broad sense refers to a kind of credit certificate and payment tool issued by banks and financial institutions to units and individuals with good credit, which can be directly consumed in designated shops and places, and can be used to deposit and withdraw money and handle transfer settlement at the business outlets of card-issuing banks and affiliated institutions.

narrow credit card refers to the credit card under the concept of bank card, that is, the bank card that can be overdrawn, including credit card and quasi-credit card. The narrow credit card is different from debit card in that the former has overdraft function and the latter has no overdraft function.