Advance Deposit Account - A debit account into which a mailer deposits funds that are maintained by the USPS and from which postage is later deducted at the time of mailing. (Also called trust account.) 

Automation–Compatible Mail - Mail that can be scanned and processed by automated mail processing equipment such as a barcode sorter. 

Balloon Rate - A rate charged for Priority Mail and Parcel Post items that weigh less than 20 pounds and measure more than 84 inches but no more than 108 inches in combined length and girth. 

 Bulk Mail - The term is generally used to describe presorting mail including Presorted First-Class Mail and Standard Mail.

Full Letter Tray - A tray filled at least 85% full with faced, upright pieces. Each tray must be physically filled to capacity before the filling of the next tray. A tray with less mail may be prepared only if less–than–full or overflow trays are permitted by the standards for the rate claimed. (Also see less–than–full tray and overflow tray.)

 

Indicia - Imprinted designation on mail that denotes postage payment (e.g., permit imprint).

Known Office of Publication - The business office of a Periodicals publication that is in the city where the original entry for Periodicals mailing privileges is authorized.

 

Mailing Permit - Permission to mail at bulk (presorted) rates. 

Meter Tape - A piece of adhesive paper that is fed through a postage meter and imprinted with postage. The meter tape is then applied to a mailpiece (usually a large envelope or parcel that is too big to fit through the postage meter).

Not Flat-Machinable – Standard Mail pieces not meeting flat-size requirements, are charged higher rates than a flat (large envelope) but lower than a  parcel rate

Nonmachinable Surcharge - A surcharge applied to Parcel Post packages that cannot be sorted on mail processing equipment because of size or weight. These mailpieces must be processed manually.  Also First-Class Letters that are square, rigid or have one or more nonmachinable characteristic are subject to the nonmachinable surcharge.

Oversized Rate - Parcel Post rate for pieces exceeding 108 inches but not more than 130 inches in combined length and girth. 

Permit Imprint - Printed indicia, instead of an adhesive postage stamp or meter stamp, that shows postage prepayment by an authorized mailer.

Postage Meter - A device that can print one or more denominations of postage onto a mailpiece or meter tape. It is available for lease only from designated manufacturers.  

Presort - The process by which a mailer prepares mail so that it is sorted to the finest extent required by the standards for the rate claimed. Generally, presort is performed sequentially, from the lowest (finest) level to the highest level, to those destinations specified by standard and is completed at each level before the next level is prepared. Not all presort levels are applicable to all mailings. 

Presorted First–Class Mailing - A nonautomation rate category for a mailing that consists of at least 500 addressed mailpieces and is sorted and prepared according to USPS standards. This mail does not bear a barcode.  

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 USPS–recommended separation). 

Presorted Rates - A discounted postage rate. In exchange for this lower postage rate, mailers must sort their mail into containers based on the ZIP Code destinations on the mail.

 

Sectional Center Facility (SCF) - A postal facility that serves as the processing and distribution center (P&DC) for Post Offices in a designated geographic area as defined by the first three digits of the ZIP Codes of those offices. Some SCFs serve more than one 3–digit ZIP Code range. 

Single-Piece Rate - The "undiscounted" or "full" postage rate available for individual pieces of Express Mail, First–Class Mail, Priority Mail, and Package Services. Single-piece rates contrast with rates available for presorted mail.  

Sort - To separate mail by a scheme or ZIP Code range; to separate and place mail into a carrier case; to distribute mail by piece, package, bundle, sack, or pouch. (Also see primary, secondary, and tertiary. 

Sortation - The distribution or separation of mail to route it to its final delivery point. (Also see mail processing.)  

Weighted Fee - The fee charged the sender for Standard Mail pieces endorsed "Address Service Requested" or "Forwarding Service Requested" that are returned as undeliverable. The fee equals the single-piece First-Class Mail rate (e.g. $0.42, $0.60) x a factor of 2.472, rounded to the next whole cent. 

Zoned Rate - A rate structure for certain Priority Mail, Periodicals (except nonadvertising portion), and Package Services (Parcel Post and Bound Printed Matter) that is based on weight and distance traveled (or zones crossed).