MACH —An abbreviation used on mail container labels that identifies the contents as machinable letters or parcels (mail that can be processed on mechanized mail sorting equipment).
Machinable —The ability of a mailpiece to be sorted by mail processing equipment. Compare withnonmachinable.
Machinable Parcel —A parcel that is of the correct size and weight to be safely sorted by mail processing machinery such as a parcel sorting machine.
Mail —Any mailable matter that is accepted for mail processing and delivery by the USPS. Also, the sum total of the mail at any time that is in USPS custody. To deposit a mailable item in a collection box or present the item (or a mailing for large quantities of mailpieces) at a Post Office or business mail entry unit.
Mail Class —The classification of domestic mail according to content (e.g., personal correspondence versus printed advertising). It is codified in the Mail Classification Schedule.
Mailing —A group of mailpieces within the same mail class and mail processing category that may be sorted together under the appropriate standards. Also, the action of depositing or presenting mail at a Post Office.
Mailing Agent —A private third party that mails on behalf of someone else.
Mailing Standards of the United States Postal Service, Domestic Mail Manual (DMM) —The USPS manual that contains the standards governing domestic mail services, descriptions of the mail classes and services and conditions governing their uses, standards for price eligibility and mail preparation, and all postage prices and fees. Domestic mail is classified by size, weight, shape, content, service, and other factors.
Managed Mail (MM) Tray —A stackable cardboard or plastic container with an enclosing cardboard sleeve and plastic strap that is used to transport letter mail to or between Post Offices.
Manifest Mailing System (MMS) —A postage payment system that enables the USPS to accept and verify permit imprint mailings that contain nonidentical-weight and/or nonidentical-price pieces. These pieces are prepared by the mailer according to certain standards and require specialized documentation.
Marking —Words or abbreviations printed on a mailpiece that show the class of mail, presort level, or ancillary service endorsement. See also endorsement.
Media Mail —A subclass of Package Services that consists of books, sheet music, printed educational material, film, videocassettes, and computer prerecorded media such as CD-ROMs. Advertising restrictions apply.
Merchandise Return Service —A service whereby an authorized company provides a customer with a special mailing label to return a shipment without prepaying postage. The company pays the return postage.
Merlin —MERLIN is an acronym for Mail Evaluation Readability Lookup Instrument, is a tool that is used by the U.S. Postal Service to assist with the acceptance of business mail.
Meter reply Mail (MRM) —A preprinted return envelope, card, or label provided by a meter license holder as a courtesy to customers on which the postage is prepaid with a meter stamp. These pieces must have a specific address and format. Compare to Business Reply Mail and Courtesy Reply Mail.
Meter Stamp —Postage printed on a mailpiece or label by a postage meter or PC Postage System. Meter stamps may be used to pay postage for all mail classes except Periodicals.
Metered Mail —Any piece of mail with postage printed by a USPS-approved postage meter or PC Postage System.
Military Ordinary Mail (MOM) —A category for Department of Defense official mail sent at Periodicals or Standard Mail prices that requires faster service than sealift transportation to, from, and between military Post Offices. This mail is moved by surface transportation to a gateway facility and from there by air at a specific transportation price and service standard. Compare with parcel airlift (PAL).
Military Post Office (MPO) —A branch of a U.S. civil Post Office operated by the Army, Navy, Air Force, or Marine Corps to serve military personnel overseas or aboard ships. Also see Army Post Office (APO) and Fleet Post Office (FPO).
Minimum Size Standard —The smallest dimensions permitted for all mailable matter or for a specific mail processing category or specific price.
Mixed Class —A mailing containing more than one class of mail. With certain exceptions, the postage on the entire piece or bundle is charged at the price of the higher class.
MXD —An abbreviation used on mail container labels that identifies the contents as mixed mail for different destinations. Usually indicates the last presort level in a sequence.