Direct mail glossary
Address Change Services (ACS)
ACS is an on-piece address correction service offered by USPS that helps to identify if the addressee has moved. It is used in conjunction with the Intelligent Mail barcode (IMb) and/or ancillary service endorsements so mail can reach the proper destination. Fees are based on the number of change of address (COA) and nixie (mail that is undeliverable for reasons other than a move) notices provided to the ACS customer.
Address Information System (AIS)
Collection of data products provided by USPS
Address Management System (AMS)
The national USPS database of every delivery address with its associated ZIP Code, ZIP+4 code, and city/state name that serves as the foundation of data for all address correction tools.
A Lob feature that ensures your mail addresses adhere to proper postal formatting and autocorrects typos and errors. Accessible through the Print & Mail address autoverify feature; does not require a separate subscription to our Address Verification API offering.
Address Type: General Delivery
An alternate delivery service that allows customers with proper identification to pick up mail at Post Offices. Provided primarily at offices without carrier delivery or for transients and customers who do not have a permanent address or who prefer not to use Post Office Boxes.
Address Type: Highway Contract Route
A route of travel served by a postal contractor to carry mail in bulk over highways between designated points.
Address Verification (AV)
A reporting dashboard offered in the Lob platform to view deliverability and mail speed on a per-segment basis that can be filtered and sorted by metadata tags.
API Rate Limit
A rate limit is the maximum number of calls you want to allow in a particular time interval. Lob’s standard API rate limit is 150 requests per 5 seconds per endpoint. The POST /v1/us_verifications and POST /v1/us_autocompletions endpoints have a limit of 300 requests per 5 seconds for all accounts.
Application Programming Interface (API)
An API is a software intermediary that allows two applications to talk to each other.
Batching similar size/material mail pieces together to optimize operations as well as reduce postage cost.
Bleed refers to the color that extends beyond the trim area of a printing space. The item is printed on an oversized sheet that is cut down to size giving the appearance that the image is bleeding off the edge of the paper.
Another name for USPS Standard Mail, or Marketing Mail.
A Lob customization feature that allows customers to configure a window of time in which mail orders can be canceled from being printed and sent even after an API request has been made.
A check is a written, dated, and signed instrument that directs a bank to pay a specific sum of money to the bearer. The person or entity writing the check is known as the payor or drawer, while the person to whom the check is written is the payee. The drawee, on the other hand, is the bank on which the check is drawn.
CMYK is an acronym for Cyan, Magenta, Yellow, and Black. The CMYK color model describes the full color printing process, where every image is color separated into the 4 colors in specific dot patterns that vary in size and frequency to create a combination of any color with a fraction of the ink. The CMYK color space works on a subtractive color spectrum, and is primarily used for physically printed material and uses ink to display color. Colors result from reflected light. When all spectrums from the CMYK color space overlap, the result is black.
Coding Accuracy Support System (CASS)
A USPS certification process offered to mailers, service bureaus, and software vendors that standardizes addresses in address lists and improves the accuracy of matching each standardized address to the proper delivery point code, ZIP+4 code, 5-digit ZIP Code, and carrier route code.
The process of color matching is to find and approve colors that match on-screen and off-screen. This ensures that colors that you see on-screen are accurate once the design is printed. The process entails looking at the hue, saturation, and brightness of the colors on-screen and making sure they are reflective of what you will see when you receive the final product.
Commercial Mail Receiving Agencies (CMRA)
A private business that acts as the mail-receiving agent for specific clients. The business must be registered with the Post Office responsible for delivery to the CMRA.
Customers have the ability to design and order customized standard #10 outer envelopes (single-windowed) through our dashboard.
Custom Return Envelopes
Customers have the ability to design and order customized standard #9 return envelopes (no window and single-windowed) through our dashboard.
A single addressable mailbox or location where mail can be delivered. All delivery points have a digit between 00-99. Combined with a ZIP+4 code, the DP and ZIP+4 are a unique identifier for every deliverable address in the US.
Delivery Point Barcode
A general term for a POSTNET barcode that contains the 9 digits of the ZIP+4 code plus 2 digits, which are generally the last 2 digits of the primary street address number (or Post Office Box, etc.). The barcode can also be formed from firm (unique) 5-digit ZIP Codes and individual (unique) ZIP+4 codes.
Delivery Point Suffix
A unique Royal Mail 2-character code (the first numeric & the second alphabetical – e.g. 2B), which, when added to the Postcode, enables each live Delivery Point to be uniquely identified.
Delivery Point Validation (DPV)
Delivery Point Validation (DPV) is a USPS product that provides the highest level of address accuracy checking. In a DPV process, the address is checked against the USPS Address Management System (AMS) data file to ensure that it exists as an active delivery point. We can determine DPV by using the associated DPV code, which consists of several sub-fields that provide additional context on the given address. At Lob, we simplify this code further by breaking it down into fields in the AV response.
Detailed Deliverability Data
Beyond simply verifying if an address is deliverable, Lob returns if it’s a business or residential address, the county that it is in, and even the specific latitude and longitude.
Dots Per Inch (DPI)
Dots per inch (DPI or dpi) is a measure of spatial printing, video or image scanner dot density, in particular the number of individual dots that can be placed in a line within the span of 1 inch.
Double sided - typically in reference to how artwork is printed on a sheet.
Early Warning System
A value of "true" means the address is not yet able to receive deliveries (e.g. new construction)
File Transfer Protocol (FTP)
FTP allows the transfer of data between computers over an internet connection and remotely store files on an FTP server. It is used in some commercial printing environments as a means to transfer a print job to a server, where it is then printed. allows you to transfer data between computers over an internet connection and remotely store files on an FTP server.
First Class Mail (FC Mail)
Lob's default USPS mailing class option for all mailpieces (available in the US and internationally) that provides higher postage rates at faster speeds. First Class domestic mail takes 4-6 business days and international mailings take an additional 5 to 7 business days.
A flat is a common name for a large envelope that is a rectangular mailpiece no thicker than 3/4 inch.
Google Tag Manager (GTM)
Google Tag Manager lets users track advertising ROI
The indicia should essentially be considered a stamp for mass-mailing purposes. However, rather than buying individual stamps for every mailpiece, the indicia connects each mailpiece to Lob's EPS account so that USPS can subtract the correct amount of postage per mailpiece.
Intelligent Mail barcode (IMb)
Intelligent Mail Barcode (IMb) is a 65-bar Postal Service barcode used to sort and track letters and flats. It allows mailers to use a single barcode to participate in multiple Postal Service programs simultaneously, expands mailers' ability to track individual mail pieces, and provides greater mail stream visibility. The IMb is required for use on letters and flats prepared for automation prices. This requirement affects First-Class Mail postcards, Certified Mail, and any other mail using extra services currently available and appropriate for the class and shape of mail prepared for automation prices.
Intelligent Mail package barcode (IMpb)
Intelligent Mail Package Barcode (IMpb) is the Postal Service's next generation tracking barcode for commercial parcels and Extra Services, including Priority Mail and Priority Mail Express flat-rate envelopes. The IMpb provides better end-to-end tracking visibility with the added benefits of automatic insurance and lower rates for IMpb compliant providers. Compliance with the IMpb requirement includes electronic upload of delivery address information in addition to the labeling requirement.
International Service Centers (ISC)
USPS-established ISCs distribute and dispatch both incoming and outgoing international mail received from a designated service area to specific foreign countries or to gateway exchange offices. The five ISCs are located in New York, Miami, Chicago, Los Angeles, and San Francisco.
In Transit Mail Tracking
This ‘digital postmark’ provides real-time visibility into how your mail pieces are progressing through the mail stream, including an auditable record and automated webhook.
Letters are a written means of correspondence with another individual or business entity, mailed in a sealed envelope. A letter can be comprised of an invoice, marketing message, personal note and any other item that fits into a business-sized envelope.
Locatable Address Conversion System (LACS or LACSlink)
Supports the conversion of rural-style addresses to street-style addresses, including Rural Routes and Highway Contract Routes.
Lowest Common Denominator (LCD)
Part of the DPV product. Binary data table that contains nine-digit ZIP Codes and four-digit add-on’s that are used in forming an EMDP.
Magnetic Ink Character Recognition (MICR)
MICR is a machine-readable text used primarily to identify and process checks. The MICR on a check is the string of characters that appears at the bottom left of the check. It consists of three groups of numbers, including the 9-character bank routing number, the 12-character account number, and the 4-character check number.
Tracking event that provides the confirmed date and time of handoff from Lob's commercial printers in our Print Delivery Network to the USPS on a per mailpiece basis.
Also known as Standard Class Mail, an alternate USPS mail class option that provides lower postage rates, but at slower speeds than USPS First Class mail. Marketing Mail may take 7-21 business days, and is only available for US domestic delivery.
Metadata tags can be applied to each API request to segment and attribute your mailings. Additionally, our search function allows you to filter by these metadata tags to find all mail pieces that fit your chosen search parameters.
National Change of Address (NCOA)
NCOA or NCOALink is a secure USPS dataset of approximately 160 million permanent change-of-address (COA) records consisting of names and addresses of individuals, families, and businesses who have filed a change-of-address with the USPS in the last 48 months. NCOALink enables mailers to process mailing lists and update lists with new addresses prior to mailing. The NCOALink data is provided on a regular basis to companies that have been licensed by the US Postal Service.
NCOALink PAF: Licensee
Customers who have signed license agreements with the Postal Service, receive files from customers for NCOALink® processing. Performs the actual processing of the LIST against the National Change of Address data.
Network Distribution Center (NDC)
A network distribution center (NDC) is a highly mechanized mail processing plant of the US Postal Service that distributes standard mail and package services in piece and bulk form. The USPS currently maintains 22 NDCs in the US.
The yellow “NIXIE” label marks Undeliverable As Addressed (UAA) mail (for reasons other than a move). There are over 20 possible Nixie or UAA codes that can be displayed on returned mail that provides context on why the mail piece was returned.
Personal Identifiable Information (PII)
Any information that permits the identity of an individual to be directly or indirectly inferred, including any other information that is linked or linkable to that individual. PII can be information that directly identifies an individual (e.g., name, address, social security number or other identifying number or code, telephone number, email address, etc.) or information that indirectly identifies individuals in conjunction with other data elements, including a combination of gender, race, birth date, geographic indicator, and other descriptors. PII is a form of Sensitive Information.
Postal Numeric Encoding Technique
Barcode method to encode ZIP Code information on letter-size and flat-size mail that can be read for sorting by automated machines.
A USPS system that offers a Web-based alternative to existing manual mailing processes with an electronic suite of services designed exclusively for business mailers.
Formerly known as RIBBS USPS, PostalPro is a website for professional mailers and service providers. Visit https://postalpro.usps.com/.
UK equivalent of Zipcode
Postcode Information File (PIF)
The USPS PIF file is used to help the barcoding of mail. Delivery point suffix (DPS) & checksum information is required to create barcodes on mail and PIF supplies these; useful if your database or PAF product does not include it.
Print Delivery Network (PDN)
Lob's proprietary network of commercial printers that handle mail production and order fulfillment before handing off mail to the USPS, ensuring fast time-to-delivery for our customers.
Priority Mail Queuing
This is the highest prioritization of Lob's customer mail production within our Print Delivery Network (PDN) to ensure our commitment to fast speed-to-market.
Processing Acknowledgement Form (PAF)
USPS requires a PAF to be signed by customers who want to use NCOALink data through Lob. TrueNCOA is required to maintain a PAF for our customers to stay compliant with the Privacy Act of 1974. USPS provides change of address information through the use of NCOALink processing. For this reason, they identify mailers through the PAF. The PAF indicates that mailers (such as Lob customers) understand that the use of the COA data is restricted. In addition, licensees are also protected by the PAF if a mailer abuses the intended use of the product.
Return to Sender (RTS)
A common policy used by post carriers to handle items that could not be delivered. If an item could not be delivered for any reason, the item would be sent back to the indicated return address if First Class mail.
RGB is an acronym for Red, Green, and Blue, and is primarily used on digital displays. RGB uses the transmitted light from digital devices to display the resulting color. RGB color space is an additive color spectrum, thus when all spectrums from the RGB color space overlap, the result is white (which is opposite of the CMYK color space).
Scheduled Data Deletion
A scheduled data deletion service offered by Lob to programmatically scrub data of your choosing from our servers at a specified cadence.
Lob feature that enables mail pieces to be scheduled to be printed and sent up to 180 days in the future.
Sectional Center Facility (SCF)
A destination sectional center facility (SCF) is a processing and distribution center (P&DC) of the US Postal Service that serves a designated geographical area defined by one or more three-digit ZIP Code prefixes. A SCF routes mail between local post offices and to and from network distribution centers (NDCs) and Surface Transfer Centers (STCs), which form the backbone of the network.
Secure File Transfer Protocol (SFTP)
SFTP uses secure shell encryption to provide a high level of security for sending and receiving file transfers between different systems. SFTP provides several methods to fulfill the authentication of a connection beyond a standard FTP, such as user IDs and passwords, SSH keys, or combinations of these. Enterprises often use SFTP to achieve file transfer compliance typically required for HIPAA, GDPR, and other regulatory regimes.
A promotional mailer that's sent without an envelope, usually for marketing purposes. Typically created from a commercially printed cardstock, which can be folded into panels and secured with adhesive tabs or glue spots to keep it tightly closed during transit. Lob offers single-panel postcards and bi-fold panel configurations.
Sensitive PII (SPII)
Sensitive Personally Identifiable Information is PII that requires stricter handling guidelines because of the increased risk to an individual if the data is inappropriately accessed or compromised. Some categories of PII are sensitive as stand-alone data elements, including Social Security number (SSN) and driver’s license or state identification number. Other data elements such as citizenship or immigration status, medical information, ethnic, religious, sexual orientation, or lifestyle information, in conjunction with the identity of an individual (directly or indirectly inferred), are also SPII.
Service Type ID (STID)
Service Type ID is a 3-digit numeric code used by USPS within the IMb on a mailpiece that identifies the address correction or other electronic services desired. The STID Table allows you to determine which STID to use based on the mail class, address correction option, use of IV®-MTR and whether the mail contains a Full Service or Basic IMb.
1 sided - typically in reference to how artwork is printed on a sheet.
Standard Class Mail
Also known as Marketing Mail, an alternate USPS mail class option that provides lower postage rates, but at slower speeds than USPS First Class mail. Standard Class mailings may take 7-21 business days, and is only available for US domestic delivery.
Tap envelope to see if address is falling outside of window.
United States Postal Service (USPS)
Also known as the USPS or US Postal Service, for short. The United States Postal Service is an independent agency of the executive branch of the US federal government responsible for providing postal service in the US, including its insular areas and associated states.
User Roles and Permissions
Enterprise-grade user permissions to limit visibility and access to certain features within the Lob dashboard.
Worldwide Address Validation
With data from over 240 countries and territories around the world, Lob verifies deliverability of both domestic and international addresses.
The nine-digit USPS code composed of two parts: 1. the first five digits (i.e., the ZIP Code) that identify the sectional center facility and delivery area associated with the address 2. the four-digit code: the first two additional digits designate the sector (a geographic area) and the last two digits designate the segment (a building, floor, etc.) Also known as "add-on"