Google’s Answer
A bank account number is a number that is tied to your bank account. If you have several bank accounts, such as personal, joint, business (and so on), each account will have a different account number.
Our Answer
A bank account number is (in the UK at least) an eight digit number that identifies your account held with a specific bank. You may have several accounts with the same bank, current, savings, joint which will all have a different account number to identify them.