Glossary

Card Identification Number/Card Identifier (CID)

An American Express and Discover verification process that utilizes a non-embossed three- or four-digit number printed when authorizing credit card transactions where the physical card is not present. On American Express cards, the CID is a four-digit code printed on the front of the card. On Discover cards, the CID is a three-digit code printed next to the card number in the signature panel.