ABA (American Bankers Association):
The national trade association of commercial banks.

ABA Routing Number:
Also referred to as Transit Routing Number. Directs electronic ACH deposits to the proper bank institution.

Account Number:
A unique sequence of numbers assigned to a cardholder account that identifies the issuer and type of financial transaction card.

ACH (automatic check handling):
A form of electronic payment. Funds or payments can be transferred electronically in two ways: by wire transfer or through an automated clearinghouse. Wire transfer is an online, real-time payment system designed to handle large-dollar, time-critical payments, mostly between large banks. ACH, in contrast, is designed to be an "electronic check." It is typically used to process high volumes of relatively small-dollar payments for settlement within one or two business days. ACH transactions are settled in a manner similar to the way checks are settled: The clearinghouse takes all ACH files received daily from its member banks, sorts them by the originating bank (the bank where the check was cashed or deposited) and the paying bank (the bank against which the check was drawn), totals the accounts, and credits or debits appropriate accounts accordingly.

Acknowledgement:
The transmission of a short packet from the receiving device to the sending device indicates that the data has been received error-free.

Acquirer:
A bank that sponsors merchants for the acceptance of credit card transactions.

Acquiring Bank:
The bank that maintains the merchant relationship and receives all transactions from the merchant.

Acquiring Bank or Acquirer:
A financial institution that provides accounts for merchants. It is also called a merchant bank, or acquirer. The acquiring bank processes the merchant's transactions and credits payment to the merchant account. Your merchant account at the acquiring bank receives funds from a cardholder when a transaction is complete. Acquirers are so named because they acquire a merchant's sales tickets and credit the order value to the merchant's account.

Address Verification System:
Address Verification Service is a system available to merchants who key transactions which matches the street number and zip code of the cardholder with the information given to the merchant. This allows the merchant to verify that the person requesting the goods or services is the person who owns the cards.

ADSL (asymmetric digital subscriber line):
A communications protocol for connecting computers and other electronic devices to a network, such as the Internet. ADSL offers more bandwidth than current telephone modem connections. ADSL can operate over most existing telephone lines but is currently available in only a few areas and generally costs more.

Approval:
A code issued by a card issuing bank allowing a sale to be charged against a cardholder's account. Approval means that the amount is within the cardholder's remaining credit limit and the card has not been reported lost or stolen. Approvals are requested via an AUTHORIZATION.

Approval/Authorization:
All participants in the chain from the retailer to the cardholder have said that they are ready, willing, and able to complete this Sale, Refund or PreAuth. Note that money does not actually flow out of (or back into) the cardholder's account upon Approval/Authorization. Rather, the transaction is queued for completion during the next batch closure.

AMERICAN EXPRESS (Amex):
An organization that issues cards and acquires transactions, unlike VISA and MASTERCARD, which are bank associations.

AMEX:
Abbreviation for American Express. An organization that issues travel and entertainment cards and acquires transactions.

Arbitration:
The procedure used to determine the responsibility for a chargeback-related dispute between two members.

ASP (active server page):
An HTML page that includes one or more scripts, or small embedded programs, that are processed on a Microsoft Web server (Internet Information Server) before the page is sent to the user. Typically, the script in the Web page (at the server level) uses input from a user's request to access data from a database and then builds or customizes the page before sending it to the requester.

ATM:
ATM is an acronym for Automated Teller Machine.

Authentication:
Identification of individuals and businesses through the use of digital certificates.

Auth Only:
A transaction in which the merchant does not intend to charge the cardholder until a later time, if at all. See PRIOR AUTHORIZATION.

Authorization:
The request to charge a cardholder. Reduces the cardholders "Open to Buy" but does not actually charge the account. Authorization must be FORCED in order to charge the account. If not used within a certain time period, the authorization will expire. Time period determined by issuing bank.

Authorization Center:
A department that electronically communicates with a merchants request for an authorization on credit card transactions to the cardholders bank and transmits the authorization via voice authorization or electronic point of sale equipment.

Authorization Code:
The numerical or alphanumerical code sent by the card issuer, given to a sales transaction as verification that the sale has been authorized. The authorization code is always included on the merchant sales draft.

Automated Clearing House:
A method of transferring funds between banks via the Federal Reserve System used by most, but not all, financial institutions.

Average ticket:
The average size of a merchant's bankcard transaction. Generally used in pricing decisions and calculations.

AVS (address verification system):
In 1996, VISA/MasterCard headquarters introduced a new regulation requiring all businesses that manually key in the majority of their credit card transactions to have a special fraud prevention feature on their credit card processing equipment. This feature is referred to as an address verification system (it checks to see that the billing address given by the customer matches the credit card). If you opt not to use AVS, VISA and MasterCard will not support your transactions and will charge you an additional 1.25% on those sales.