M

MAC

Message Authentication Code; a quantity of data based on the contents of a message, used to confirm that it has been received as transmitted.

manual entry

The credit card information that is entered via the transaction terminal.

MasterCard

An association of banks that governs the issuing and acquiring of MasterCard credit card transactions and Maestro debit transactions.

MBONE

Multicast Backbone; a special network backbone used to transmit multicasts (including coverage of standards meetings and other content, in real time) over the Internet.

member

A financial institution that is a member of Visa USA and/or MasterCard International. A member is licensed to issue cards to holders and/or accept merchant drafts.

Member Service Provider

A MasterCard term for a company that is sponsored by an acquiring bank to solicit and sometimes support merchants.

merchant

A retailer, or any other entity (pursuant to a Merchant Agreement), that agrees to accept credit cards, debit cards, or both, when properly presented.

Merchant Agreement

A written agreement between a merchant and a bank (or possibly a merchant, a bank, and ISO) containing their respective rights, duties, and warranties with respect to acceptance of the bank card and matters related to bank card activity.

merchant bank

A bank that has entered into an agreement with a merchant to process bank card transactions, also called the acquirer or acquiring bank.

merchant category code

A code assigned by an acquirer to a merchant to identify the merchant’s principal trade, profession, or line of business. This four-digit code is also know as the SIC code.

merchant identification number

A unique number that is assigned by the acquiring bank to identify a merchant.

merit

The qualification levels for a MasterCard transaction. Merit III is the highest discount, followed by Merit II, Merit I, and then Standard.

MICR number

The Magnetic Ink Check Reader (MICR) number is the string of numbers on the bottom of a check.

MIME

Multipurpose Internet Mail Extensions; a specification for the linking and transfer of nontext files with Internet e-mail and other IP applications (including Usenet news).

MO/TO

Mail Order/Telephone Order credit card transactions.

multicast

The transmission of network traffic to some, but not all, hosts connected to the network or internetwork.

multihomed host

A system connected to an internetwork on two or more different individual networks. Routers and gateways are, by definition, multihomed hosts, because they link two or more separate networks.