0 abbreviation for Card Verification Value: a number on a credit card or debit card (= a card used for payment), usually three digits (= individual numbers) on the back of the card, that is used to prove that the person making the payment has the card in their possession:
When it was introduced, the point of the CVV was to ascertain that a cardholder was actually in possession of a specific card for telephonic transactions.
The CVV is just one element of our security regime and its introduction had a significant downward effect on card fraud.
I'm trying to book a flight home to London and the CVV number on my card has rubbed off!