Address Verification Service (AVS)
A check in which the card issuer compares the digits of the billing address the customer typed with the address it has on file.
AVS is one of the oldest fraud controls in card-not-present commerce, dating from the mail-order and telephone era. The merchant sends the street number and postcode along with the authorisation, and the issuer replies with a one-letter code: Y for a full match, Z when only the ZIP matches, N for no match, and a handful of codes that amount to "no idea". AVS blocks nothing by itself. It's up to the merchant whether a wrong postcode is a reason to decline.
It mostly works in the US, Canada and the UK. Elsewhere, issuers frequently answer that the service isn't supported, and it offers no protection against friendly fraud, where the address is of course correct. In Europe, strong customer authentication has largely taken over the job.