Credit Card Glossary: Terms and Definitions
Credit card number
A credit card number is the unique number imprinted on a credit card. The first six digits on a credit card are called the issuer identification number. They identify the issuer — Discover, or American Express, for example. The remaining digits of a credit card number are unique to the individual card. Credit card numbers are usually embossed, a remnant the days when a physical impression of credit cards were made through zip-zap machines.