Payment gateway
The code that transmits customer orders to and from a merchant bank's transaction authorizing agent.

Personal Identification Number (PIN)
An alphanumeric or numeric code used to identify a person using a credit or other payment card.

Point of Sale Terminal (POS)
The credit card processing device which reads the magnetic strip on the back of the card. After sliding or “swiping” the card, the terminal contacts the credit card clearinghouse to authorize the charge, displays an authorization code, and usually prints a card transaction slip which is then signed by the customer. Most retail stores use this method of card processing because it is simple to use, fast, and accurate. Also called a Credit Card Terminal, or Card Swipe Machine.

Processing bank
Once a credit card number is entered, the processing bank is the bank that processes the actual transaction.