CVV is a new authentication procedure established by credit card companies to further efforts towards reducing fraud for internet transactions.
It requires the card holder to enter the CVV number from the card at transaction time to verify that the card is on hand.
Each credit card company has its own name for the code, but it works the same for all cards.
The CVV/CVC code can be found on the back panel of most Visa/MasterCard cards, after the full 16-digit account number. For American Express cards
it is usually on the front.