A card security code is a three- or four-digit number on the back of credit and debit cards that ensures the authenticity of transactions when a physical card is not presented at the point of sale.

The Card Security Code is the 4 digit number located above the account number on the face of the card, sometimes on the left side and sometimes on the right. If your CSC number has been scratched off ...

It doesn't matter what you call them -- a card security code (CSC), card verification value (CVV or CV2), card verification code (CVC) or even a card.