The most popular definition of a credit card is: when your shopping needs exceed your payment ability or you don't want to use cash, you can borrow money from the bank without paying any interest or handling fees. A credit card is the proof that the bank agrees to lend you money. It will tell you how much you can borrow from the bank and when you need to pay it back. Also, you can withdraw cash directly from an ATM even when there's no money in your credit card account. These are all based on credit.