Definition differences and functional differences.

1. Definition difference: Account number refers to a user account opened in a bank or other financial institution, which is used to record the user's capital flow and transaction records. An account number consists of a string of numbers or letters. Card number refers to the unique identification number on a bank card or credit card, which is used to identify and distinguish different cards. The card number is the long series of numbers in the middle of the bank card.

2. Functional differences: One account can be associated with multiple card numbers. One bank account can be associated with multiple debit or credit cards, and each card has its own card number. This way users can conduct different types of transactions through different card numbers. One card number can also be associated with multiple accounts. A credit card can be associated with multiple repayment accounts for repayment. In this case, the card number is just a pass mark. What really matters is the associated account number, which is used for the inflow and outflow of funds.