Glossary of Terms




The location to which the Postal Service is to deliver or return a mailpiece. It consists of certain elements such as recipient name, street name, and house number, and city, state, and ZIP Code. (2) The portion of an envelope or parcel which shows the delivery location of the recipient of the mailpiece.

Address Change Service (ACS)

A process that centralizes, automates, and improves the processing of address correction requests for participating mailers. The Postal Service transmits address correction information to a central point where the changes are consolidated electronically, by unique publication or mailer identifier, and transmitted to the mailer.

address correction service

If mail cannot be delivered as addressed, this service allows the sender on request, using the appropriate ancillary service endorsement, to obtain the addressee’s new (forwarding) address (if a change-of-address order was filed), or the reason the mail cannot be delivered as addressed.

advance deposit account

An account into which a mailer deposits funds that are maintained by the Postal Service which postage, per piece charges, and other fees are deducted.

advertising mail

A sales product or promotional message mailed directly to customers or prospective clients. Also known as direct mail.

ancillary service

Forwarding, return, or address correction service included within a mail class. Depending on the mail class, these services are performed at a charge or at no additional charge, if and when the service is actually provided. Also see forward.

area distribution center (ADC)

A mail processing facility that receives mail and distributes mail destined for a wide range of specific ZIP Codes.

aspect ratio

The dimension of a mailpiece expressed as a ratio of length (the direction parallel to the address) divided by height. For example, a postcard 5-1/2 inches long by 3-1/2 inches high has an aspect ratio of 1.57. An aspect ratio between 1.3 and 2.5, inclusive, is required for letter mail automation compatibility. For First-Class Mail letters, aspect ratio is used to determine whether a nonstandard surcharge applies.

automated area distribution center (AADC)
An area distribution center that uses automation to process automation-compatible mail. Also see area distribution center.

automation-compatible mail auxiliary service facility (ASF)

A mail processing facility that has its own service area and functions as a bulk mail center (BMC).

automation discount

A postage reduction offered to mailers who barcode their letters and flats and meet addressing, readability, and other requirements for processing on automated equipment.


balloon price

A price charged for Priority Mail (zones 1-4) Parcel Select, and Parcel Post items that weigh less than 20 pounds and measure between 84 and 108 inches in combined length and girth.

barcode (BC)

A series of vertical bars and spaces that represent a numeric designation such as a ZIP Code or package identification code.
The barcode facilitates automated processing by barcode readers and scanners.

barcode discount

Available for certain types of mail that bear a specified type of barcode and meet minimum volume requirements.

Bound Printed Matter (BPM)

A subclass of Package Services for material that weighs no more that 15 pounds and consists of permanently bound sheets, at least 90 percent of the sheets are printed with advertising, promotional, directory, editorial matter or a combination of these. Not available at retail outlets.

bulk mail

Mail that is generally rated for postage partly by weight and partly by the number of pieces in the mailing. A price discount is given based on the mail preparation work done by the mailer and the place of mail deposit. Mail that meets postal specifications concerning design, size, machine readability, and characteristics
so that it can be scanned and processed by automated mail processing equipment.

bulk mail center (BMC)

A highly mechanized mail processing facility that is part of the National Bulk Mail System. This facility distributes Standard Mail and Periodicals in containerized form such as sacks and pallets, and Package Services in both piece and containerized form.


A group of addressed pieces assembled and secured together to make up a basic unit of bulk mail for processing purposes.

business mail

Any mail sent by any business, using any possible mailing method and service.

business mail entry unit (BMEU)
The area of a postal facility where mailers present mailings for acceptance that require postal verification, such as presorted and permit imprint mailings.

business reply mail (BRM)

A service that allows a permit holder to receive First-Class Mail and Priority Mail back from customers and pay postage
only for the returned pieces. These pieces must have a specific address and format. When the mail is delivered back to the permit holder, postage and
per piece charges are collected, usually through an advance deposit account.

Ccarrier pickup

A service at that allows customers to schedule
a pick-up of their Express Mail, Priority Mail, and International packages at the time of their next regular mail delivery.

carrier route (CR)

(1) The range of addresses assigned to one carrier for the delivery of mail. This can include city routes, rural routes, and highway contract routes.

(2) A discounted postage price available for all pieces to the same city route, rural route, highway contract route, Post Office box section, or general delivery unit.

carrier route sortation

The practice of sorting mail by carrier route to qualify for reduced postage prices. The term is a general descriptor of the available prices for this type of preparation, which include Enhanced Carrier Route Standard Mail, carrier route Periodicals, and carrier route Bound Printed Matter.

certificate of mailing

An extra service that provides a receipt as evidence of mailing.

Certified Mail

An extra service that provides
the sender with a mailing receipt and delivery information. A record of delivery with the recipient’s signature is kept by the Postal Service. Certified Mail must be sent as First-Class Mail or Priority Mail and may be combined with return receipt and/or restricted delivery service.


The grouping of mailable matter into mail classes and subclasses by price categories, according to content, weight, size, and preparation standards.

Classroom Price

A Periodicals price that is available to an authorized mailer of educational, scientific, or religious publications for scholastic or religious instruction.


A service at that allows customers to print shipping labels from their computers with or without postage for Express Mail and Priority Mail. Customers pay for postage online with a credit card, and the labels will print with PC Postage indicia.

coding accuracy support system (CASS)
A service that improves the accuracy of delivery point barcodes, ZIP+4 codes, 5 digit ZIP Codes, and carrier route information on mailpieces.

collection box

A blue street mailbox with the Postal Service logo used by the public to deposit mail. Each box is equipped with a security lock. It has a uniform appearance and a nationwide identification system that distinguishes the type of service provided at each box.

collect on delivery (COD)

An extra service that permits a mailer to mail an article and have its price and the cost of postage plus a service fee collected from the recipient.

commercial mailing services

Services that allow mail to be sent at reduced prices, including First-Class Mail, Standard Mail, Periodicals, Parcel Select and Package Services. Discount mailing services, also called bulk mail, direct mail, advertising mail, and presorted mail, usually involve higher volumes of mail and require sortation and special preparation.

commercial prices

Reduced postage prices offered to mailers in exchange for higher standards of mail preparation, sortation, and destination entry.

Computerized Forwarding System (CFS)
A centralized program that provides address correction information to mailers and forwards mail to customers who have moved and filed Form 3575, Change of Address Order.

courtesy reply mail (CRM)

A preaddressed return envelope or postcard that business mailers provide to a customer for returning a remittance, order, or response. The customer pays the postage..

Delivery Confirmation
An extra service that provides the date and time of delivery or,
if delivery was attempted but
not successful, the date and time of the delivery attempt.

delivery point barcode (DPBC)

A POSTNET barcode that represents the ZIP+4 code generally and the last two digits of the primary street address number (or Post Office box, etc.) and a correction digit. The DPBC allows automated sortation of mail to the carrier level in walk sequence.

delivery sequenced mail

Mail that is arranged by a mailer in delivery order for a particular carrier route.

delivery unit

The postal facility where the carrier cases the mail for delivery.

destination bulk mail center (DBMC) price
A price available for Standard
Mail, Parcel Select, and Bound Printed Matter that is properly prepared, transported, and entered by the mailer at the BMC or other designated postal facility that serves the delivery address on

the mail.

destination delivery unit (DDU) price
A price available for Periodicals, Standard Mail, Parcel Select, and Bound Printed Matter that is properly prepared and entered by the mailer at the postal facility that serves the delivery address on the mail.

destination entry

The process of transporting and depositing mail at the postal facilities that serve the addresses on the mailpieces in a mailing. The mailer receives additional discounts for destination entry mail.

destination sectional center facility (DSCF) price
A price available for Periodicals, Standard Mail, Parcel Select, and Bound Printed Matter that is properly prepared, transported, and entered by the mailer at the SCF or other designated postal facility that serves the delivery address on the mail.

dimensional weight

Low density Priority Mail parcels shipped to zones 5-8 are charged at a dimentional weight or pound weight, whichever is greater, when the parcel exceeds 1 cubic foot.

direct mail

Another name for advertising mail sent to targeted markets to help renew, maintain, or grow business.

Domestic Mail Manual (DMM) Postal Service manual that contains the standards and prices for domestic mail services.

drop shipment

Typically the movement of a mailer’s product on private transportation from the point of production
to a postal facility closer to the destination of those pieces.



The qualification standards, such as content, shape, and preparation, that a mailpiece must meet for specific prices or discounts.


An authorized marking on a mailpiece that shows handling instructions or extra services.

Enhanced Carrier Route Standard Mail
Mailpieces weighing less than 16 ounces and prepared in the sequence delivered by the letter carrier.

entry facility

The Postal Service mail processing facility that serves the Post Office at which the mail is entered by the mailer. Also called origin facility.

Express Mail

A mailing service that provides expedited delivery. This is the fastest mail service offered by the Postal Service. Global Express Guaranteed service is available from the United States to most other countries.

extra services

A mail service for a fee in addition to required postage, that provides proof of mailing, and/or delivery, or security and insurance. Extra services include Registered Mail, Certified Mail, insured mail, certificate of mailing, restricted delivery, return receipt, return receipt for merchandise, Delivery Confirmation, Signature Confirmation, and collect on delivery. Also called special services.



A USPS-licensed automated system that updates addresses by matching names and addresses with current change-of-address orders on file. A piece updated with FASTforward can be delivered directly to the new address rather than forwarded from the old address.

First-Class Mail (FCM)

A mailing service that includes all matter wholly or partly in handwriting or typewriting, all actual and personal correspondence, all bills and statements of account, and all matter sealed or otherwise closed against inspection.


Flat-size (large envelope) mail exceeds at least one of the maximum dimensions for letter-size mail (11-1/2 inches long, 6-1/8 inches high, 1/4 inch thick) but does not exceed the maximum dimensions for flats (15 inches long, 12 inches high, 3/4 inch thick). Dimensions are different for automation price flats. A flat may be unwrapped, sleeved, wrapped, or enveloped.

The measurement around the thickest part of a mailpiece.

hazardous material
Any article or substance designated by the U.S. Department of Transportation as posing an unreasonable risk to health, safety, or property during transportation.

Imprinted designations on mailpieces that indicate postage payment (e.g., metered postage or permit imprint).


A letter, card, or other item placed inside another mailpiece.

insured mail

An extra service that provides indemnity coverage for a lost, rifled, or damaged article, subject to the standards for the service and payment of the applicable fee. Insurance is available for merchandise sent as Express Mail, Priority Mail, First-Class Mail, Standard Mail, and Package Services.

International Business Reply Service
An international mail service that allows envelopes and postcards to be distributed in certain foreign countries for return without postage prepayment to the original sender in the United States.

International Mail Manual (IMM) The Postal Service manual containing standards and prices for mailing from the United States to other countries.

For letters and postcards, the measurement parallel to the direction of the address of a mailpiece as read. For flats and parcels, length is the longest dimension.


Letter-size mail. Mailpieces, including cards, that are at least 5 inches long, 3-1/2 inches high, and 0.007 inches thick, but not more than 11-1/2 inches long, 6-1/8 inches high, 1/4 inch thick, or over 3.5 oz.

letter shop

See mail service provider.

Library Mail

A subclass of Package Services for items sent to or from or exchanged between academic institutions, public libraries, museums, and other authorized organizations. Books, sound recordings, academic theses, and certain other items may be mailed at the Library Mail price if properly marked.

line-of-travel (LOT) sequence

A sequence required for some Enhanced Carrier Route and carrier route prices in which mailpieces are arranged by ZIP+4 codes in the order in which the route is served by the carrier. The mailpieces are sequenced in delivery order.

The ability of a mailpiece to be sorted by mail processing equipment. (Compare with nonmachinable.)

machinable parcel

A parcel that can be safely sorted by mail processing machinery.

mail class

The classification of domestic mail according to content (e.g., personal correspondence, which must be mailed as First-Class, Priority Mail or Express Mail).

mail service provider

A private vendor that provides a wide range of mailing services such as printing, address quality and standardization, sorting, transporting, and entering mail for a client.


A group of mailpieces within the same mailing service 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 agency

See mail service provider.

mailing fee

An annual fee charged for mailers to use certain discount mail options.

mailing process

Steps followed to prepare, pay postage, and enter mail with the Postal Service. Each method of mailing has its own process.

mailing service

Class of mail (that is, Express Mail, First-Class Mail, Standard Mail, Periodicals, Parcel Select, and Package Services). The classification of domestic mail is based mainly on content (such as personal correspondence versus printed advertising).


A single addressed card, letter, flat, or parcel.

mailpiece design analyst

Postal employees located in larger cities that specialize in helping customers with the design of their mailpieces.

manifest mailing system

A postage payment system that enables the Postal Service to accept and verify the weight or price of permit imprint mailings. Often used for non-identical weight pieces.


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 charts, film, videocassettes, CD-ROMs, or other computer-readable media.

Merchandise Return Service

An extra service that allows an authorized company to provide a customer with a special mailing label to return a shipment without the customer prepaying postage. The company pays the return postage.


See postage meter.

meter stamp

Postage printed by a Postal Service-approved postage meter or PC Postage system directly on a mailpiece or a Postal Service- approved label.

metered mail

Any class of mail except Periodicals with postage printed by a Postal Service approved postage meter.

metered reply mail (MRM)

A preprinted return envelope or card provided as a courtesy to customers. The postage is prepaid by the meter license holder.

military mail

Mail that bears a U.S. military delivery or return address and that, in some stage of its transmission, is in the possession of the Department of Defense.

minimum size standard

The smallest dimensions allowable for all mailable matter. Except for keys and identification items, a mailpiece less than 1/4 inch thick must be rectangular and meet

the minimum criteria listed below; otherwise, it is nonmailable and is returned to sender:

  • At least 5 inches long

  • At least 3-1/2 inches high

  • At least 0.007 inch thick

  1. Move Update

    Addresses on all discounted First-Class Mail must be updated within 185 days before the mailing date with a Postal Service- approved method. Effective 11/23/2008 the requirement will change to 95 days, and will also include Standard Mail.

    National Change of Address Linkage System (NCOALink)
    An address correction service provided to mailers by the Postal Service through its licensees. The licensees match computerized mailing lists with change of address data, and NCOALink provides current, standardized, and ZIP+4 coded addresses for all residential and business movers before the mail enters the mailstream.

    NetPost Services

    Allows customers to create documents and address lists on a computer and transmit them electronically via the Postal Service Web site ( for printing by a third-party vendor and delivery by the Postal Service.


    Mail that cannot be sorted on mail processing equipment because of size, shape, content, or address legibility. Such mail is normally processed manually and could be subject to a surcharge.

nonmachinable surcharge

An additional charge on some First-Class Mail, Standard Mail, and Parcel Post pieces that are nonmachinable.

nonmailable matter

Items such as hazardous materials or restricted items that are not permitted in the mailstream.

nonprofit Periodicals

A discount for authorized nonprofit Periodicals publishers.

Nonprofit Standard Mail

A subclass of Standard Mail that is available to qualified organizations specified by U.S. statute and approved by the Postal Service.

oversized price
Price for pieces exceeding 108 inches but not more than 130 inches in combined length and girth.

Package Services
A class of mail that comprises four subclasses: Bound Printed Matter, Library Mail, Parcel Post, and Media Mail. There is no minimum weight limit for Package Services.


Mail that does not meet the mail processing category of letter-size or flat-size mail. It is usually enclosed in a mailing container such as a box.

Parcel Post

A subclass of Package Services with prices generally based on weight and zone.

Parcel Select

Mail that qualifies for destination entry prices and is entered at a destination bulk mail center, sectional center facility, or delivery unit.

PC Postage Technology

Secure technology used to purchase and print postage using a personal computer or other device.


A class of mail consisting of authorized magazines, newspapers, or other publications formed of printed sheets that are issued at least four times a year at regular, specific intervals from a known office of publication.


Any authorization required for specific types of services, preparation, or postage payment.

permit imprint

Printed indicia, used in place of an adhesive postage stamp or meter stamp, that shows postage prepayment by an authorized mailer.

pickup on demand

A service at that allows customers to schedule a pickup of Express Mail, Priority Mail, and Parcel Post within  a specified time frame for an additional fee.

piece price

The postage charged for each piece in a mailing. For certain discount mail, a pound price is charged in addition to the piece price.


Payment for delivery service that is affixed or imprinted onto a mailpiece, usually in the form of a postage stamp, permit imprint, or meter impression.

postage evidencing system

See postage meter.

postage meter

A secure device that generates indicia imprinted on or affixed to mailpieces to show prepayment of postage. Postage meters  are available for lease only from authorized manufacturers.

postage stamp

A gummed or self-adhesive paper stamp affixed to mail as payment for postal services.

postage statement

Documentation provided by a mailer to the Postal Service that reports the volume of mail being presented and the postage payable or affixed, and that certifies that the mail meets the applicable eligibility and addressing standards for the price claimed.


A privately printed mailing card. Compare to stamped card.

pound price

A price charged based on the weight of a mailing in addition to a piece price.

precanceled stamp

Stamps canceled by printing across the face before they are sold to mailers for bulk mailings. Also, a stamp designated by the Postal Service as a precanceled stamp without cancellation marks. These stamps are used for Presorted First-Class Mail, Standard Mail, and Nonprofit Standard Mail.

presorted mail

A form of mail preparation, required to bypass certain postal operations, in which the mailer groups pieces in a mailing by ZIP Code  or by carrier route or carrier walk sequence (or other Postal Service–recommended separation).

Pricing and Classification Service Center (PCSC)
A USPS field office that provides guidance to employees and customers on mail classification, postage prices, and mail preparation. See 608.8 for listing.

printed matter

Paper on which words, letters, characters, figures, or images (or any combination of them) not having the character of a bill or statement of account, or of actual and personal correspondence, have been reproduced by any process other than handwriting or typewriting.

Priority Mail

First-Class Mail that weighs more than 13 ounces and, at the mailer’s option, any other mail matter weighing 13 ounces or less. Most mailable matter may be sent as Priority Mail.

prohibited matter

Any material that is illegal to mail because it can kill or injure an individual or damage other mail. This includes certain poisons and controlled substances and certain flammable or hazardous material.

Qualified Business Reply Mail (QBRM)
Business reply mail that is automation compatible. QBRM pieces must meet certain design specifications and may be eligible for the lowest per piece fee available for BRM and for reduced automation First-Class Mail postage prices.

The postage cost per piece or pound to mail.

Registered Mail

Registered Mail is the most secure service offered by the Postal Service. Through a system of receipts, the Postal Service monitors the movement of a mailpiece from the point of acceptance. The sender receives a receipt at the time of mailing, and a delivery record is maintained by the Postal Service. This service also provides optional indemnity in case of loss or damage.

reply mail

Refers collectively to Business Reply Mail, Meter Reply Mail, and Courtesy Reply Mail.

restricted delivery

A supplemental mail service that generally limits who may receive an item. This service is available for a fee when used with Certified Mail, collect on delivery, insured mail, and Registered Mail.

restricted matter

Any item on which certain mailing restrictions have been imposed for legal reasons other than the risk of harm to persons or property. Examples are motor vehicle master keys, firearms, liquids and powders.

retail mailing services

Services that allow any quantity of mail to be sent at single-piece postage prices, including Express Mail, Priority Mail, First-Class Mail, and Package Services. Retail mailing services generally do not require any sortation or special preparation.

return receipt—electronic copy

An electronic return receipt requested at the time of mailing provides a copy of the signature of an addressee for an article as proof of delivery. It can be sent by fax, mail, or electronically. This extra service is available for a fee when using Certified Mail, collect on delivery, mail insured for more than $200, Registered Mail, or return receipt for merchandise. The electronic option is not available or items mailed to APO or FPO addresses or U.S. territories, possessions, and freely associated states, with the exception of Puerto Rico and the U.S. Virgin Islands.  A similar service is available for international mail.

return receipt—hard copy

The mailing card (PS Form 3811) signed by the addressee of an article and mailed back to the sender as evidence of delivery. This extra service is available for a fee when using Express Mail, Certified Mail, collect on delivery, mail insured for more than $200, Registered Mail, or return receipt for merchandise. A similar service is available for international mail.

return receipt for merchandise

An extra service that provides the sender with a mailing receipt and a return receipt. A delivery record is maintained by the Postal Service. It does not include insurance coverage and does not provide for restricted delivery.

A container generally used to transport flat-size mail, parcels, and loose-piece mail.

sectional center facility (SCF)

A postal facility that serves as the processing and distribution center for Post Offices in a designated geographical area, defined by the first three digits of the ZIP Codes of these offices. Some SCFs serve more than one 3-digit ZIP Code range.

service options

The mailing services offered by the Postal Service, including Express Mail, Priority Mail, First-Class Mail, Standard Mail, Periodicals, Parcel Post, Library Mail, Media Mail, and Bound Printed Matter.

Signature Confirmation

An extra service that provides the recipient signature and the date and time of delivery or attempted delivery.

simplified addressing

An alternative addressing format used when delivery of identical mailpieces is requested to every customer on a rural route or highway contract route, or to all Post Office box customers at a Post Office without city carrier service. Instead of listing a name and address, the mailer may use “Postal Customer.” Simplified address may also be used by government agencies for official mail sent to all stops on city routes and Post Office boxes at Post Offices with city delivery service.

single-piece mail

Mail sent using retail prices.  See retail mailing services.


The distribution or separation of mail by ZIP Codes, range of ZIP Codes, or carrier route.

special handling

An extra service that provides preferential handling in dispatch and transportation. The service does not itself insure the article against loss or damage. Special handling is available only for First-Class Mail, Priority Mail, and Package Services.


See postage stamp.

stamped card

A postcard sold by the USPS (as distinguished from a privately printed postcard) with a printed or impressed postage stamp. Compare to postcard.

Standard Mail

A mailing service (class of mail) that comprises the subclasses of Regular Standard Mail, Nonprofit Standard Mail, Enhanced Carrier Route Standard Mail, and Nonprofit Enhanced Carrier Route Standard Mail. Circulars, printed matter, pamphlets, catalogs, newsletters, direct mail, and merchandise can be sent as Standard Mail.


A division of a mailing service (class of mail). For example, the Package Services subclasses are: Parcel Post, Media Mail, Bound Printed Matter, Library Mail.


An additional fee for certain nonmachinable mailpieces.

A container used by the Postal Service and mailers to hold letters and First-Class Mail flats. It is used as a basic unit of mail quantity for purposes of preparing mail to qualify for discounted postage prices.

A system of checks used to determine if a mailing was properly prepared and if the correct postage was paid.

walk sequence
The order in which the letter carrier delivers mail for a route. This order is required for most Carrier Route presort mail.

weighted fee

The fee charged the sender for Standard Mail pieces endorsed “Address Service Requested” or “Forwarding Service Requested” that are returned as unforwardable or undeliverable.

ZIP Code
The system of 5-digit numeric codes that identifies the individual Post Office or delivery station associated with an address.

ZIP+4 barcode

A nine-digit POSTNET barcode consisting of 52 vertical bars. Also see Postal Numeric Encoding Technique.

ZIP+4 code

The nine-digit numeric code that identifies the individual delivery station, sector, and segment assigned with an address.


A number that expresses the distance that a mailpiece must travel from point of entry to point of delivery. It is based on the air mileage along a great circle line between three-digit ZIP Code prefix areas of dispatch and receipt. This mileage range is converted to a zone number. The Postal Service uses eight numbered postal zones for computing postage on mail.

zone chart

A table that shows the zone number between 3-digit ZIP Code prefix areas.

zoned price

A price structure for certain Express Mail, Priority Mail, Periodicals (except nonadvertising portion), Parcel Post, and Bound Printed Matter that is based on weight  and distance.