Glossary Terms here for any questions or confusing terms used within this website!

Absorption: This is paper’s ability to take in the liquids used in the manufacturing process: inks and adhesives. Since envelopes are often exposed to humidity in storage, which can affect the inks and adhesives, this property is highly important.

Adhesives: Envelope adhesives fall into two categories: fasteners and sealants. A fastener adheres the two seams of an envelope together, and a sealant is what allows the seal flap to stick to the back of the envelope.

A-Style Envelopes: These are the envelopes most commonly used for announcements. There are six standard sizes all of which are open-side, featuring a double side seam construction with a squared flap.

Back Gum (Seam Gum): This is the fastening adhesive used on the back seams to construct the envelope.

Banding: This is the process of placing a paper band around a certain specified number of envelopes to help count. It is common practice for greeting envelopes.

Bang Tail Envelope: This open-side envelope has an extension on the bottom flap that is perforated at the envelope’s throat. This is commonly used as an order form used by mail order companies and for credit card statement remittances.

Baronial: Commonly available in five sizes, this style of envelope has a diagonal seams that form a large pointed flap.

Basis Weight: This number represents the weight of 500 sheets of a certain grade of standard-sized paper. Therefore, 500 sheets of 29 x 20 white kraft Basis 80 would be 80 pounds.

Blank: This is what the envelope is referred to after it has been die cut but before the folding process while it is still flat.

Bleed: The image is larger than the envelope fold or edge of the blank.

Booklet: This is an open-side double side seam envelope.

Bottom Flap: This is the part of the envelope that is folded up from the bottom to create the back of the envelope.

Business Reply or Return Envelope: These are the envelopes found in mailings that allow forms and other items to be sent back. The main difference between the reply and return is who is responsible for paying the postage. With a business reply, the original sender has already paid for the postage. By contrast, the postage on a business return envelope must be paid for by the individual sending it back.

Catalog Envelope: This style of envelope has an open-end center seam and a seal flap on the shorter side.

Center Seam: This is the seam most commonly found on open end envelopes in which the back of the envelope is joined at a straight line running up the center to the throat

Clasp Envelope: Reusable metal clasp closures provide extra security for storing papers and mail. They feature a clasp on the back of the envelope and a hole on the flap to allow the clasp to come through and be folded down. They are primarily found on open end envelopes.


  • String and Button Envelope: These envelopes have a string attached to the outside seal flap that the user wraps around a button placed on the back of the envelope. These are your standard inter-departmental mail envelopes
  • Latex (Self-Seal): This sealant requires no moisture. Instead, it uses a latex gum on the seal flap and the back of the envelope which, when pressed together, seal the envelope.
  • Remoistenable Seal Gum: This is the seal gum found on common envelopes that needs to be moistened to seal the envelope.
  • Metal Clasp: A small piece of metal attached to the back of the envelope that goes through the hole in the flap when closed. The user then folds down the two pieces of metal, thus sealing the envelope.
  • Peel & Seal: A strip of release paper covers a line of gum on the flap of the envelope. When the release paper is removed, the envelope is ready to be sealed without any moisture.

Cello: This is a type of window film that is exceptionally clear.

Coin Envelope: A small open-end envelope from size #00 (1-1/16” x 2-3/4”) to #7 (3-1/2” x 6-1/2”).

Commercial Style: This is the most popular envelope for business and is often considered to be “official.” These envelopes come in many sizes and are open side, diagonal, or double side seam with a commercial flap.

Converting Only: This is the process of taking pre-printed paper and completing the manufacturing process to turn it into an envelope.

Coupon Hitch-Hiker: This remittance envelope features perforated extensions on the flap and the back flap.

Diagonal Grain Cutting: This is when the grain of the paper runs from corner-to-corner across the face of the envelope. It is also referred to as random or cross grain cutting.

Diagonal Seam: A diagonal seam going from the bottom fold to the throat of the envelope.

Die: The piece of equipment used to cut the envelope blanks and windows. It is a thick steel outline that is pressed into stacked sheets of paper.

Die-Cut: Using dies to produce the blanks and window cut-outs.

Expansion Envelope: These envelopes are made to be able to expand to fit books, binders, and other large items. They are made of heavy paper stock and can be either open side or open end. One use for expansion envelopes is art portfolios.

Envelope Printing:

  • Letterpress or Flexo: High quality process that uses raised letters on a rubber surface.
  • Litho (Offset): Ink is transferred from a special plate to a rubber blanket and then onto the printed surface.
  • Corner Card: The content found in the upper left-hand corner of an envelope such as logo and return address.
  • Indicia: Printing that occurs in the upper right hand corner of the envelope which indicates that the sender will pay the postage.
  • Tinting: Enhanced security provided by a patterned printing on the inside of the envelope.
  • Camera-Ready Art Work: This is a black-and-white copy of the completed image to be printed to make negatives for litho printing.
  • Color-Separated Art Work: Each color needs to be separated out into its own separate piece to make negatives and plates.
  • Pantone Matching System (PMS): These are the standard ink colors which are used to match against given images. This system identifies all of the colors found in these images. The Pantone system is universal.

Flaps Extended: A special request to have the envelope flaps kept open and extended when boxed for delivery.

Flush Cut: This is when the seal flap is removed which leaves the envelope open at the top.

Foil Lined: The throat and inside flap are lined with decorative foil.

Fold: All of the folded edges of the envelope. Commonly referred to with its location (side, top, or bottom folds).

Gum: The adhesive material used in envelope manufacturing

Hitch-Hiker Envelope: This envelope is used for both outbound and return response mailing.

Job Jacket Envelope: A large envelope used for storing all the elements of a print job for future reference.

Open End: An envelope with the seal flap on the shorter dimension.

Policy Envelope: An envelope with similar dimensions as #10 to #14 commercial envelopes but with an open end format.

Poly: The common window-patch material. Short for Polyclear.

Proxy Envelope: This envelope is traditionally used for mailing annual reports or proxy voting cards. It is characterized by an open-side layout with a commercial envelope attached to the outside or a small pocket behind the window.

Regular: Any commercial envelope without a window.

Remittance Envelope: Typically used as a collection envelope, remittance envelopes have a booklet or side-seam style and a long wallet-style seal flap.

Safety Fold Envelope: To ensure increased security for the envelope’s contents, this envelope follows and open side design with a large wallet flap, high throat and center seam.

Scoreline: The fold line of the flap to the body of the envelope.

Seal Gum: The adhesive applied to the seal flap of an envelope which allows it to seal.

Shoulder: The top edge of the side flaps where the envelope opens. The far edges of the throat.

Side Flaps: The parts of the envelope that fold in from the sides to create the back.

Side Seam: A type of envelope seam that is perpendicular to the envelope opening.

Side Seam Inside: A side seam that folds under the bottom flap.

Side Seam Outside: A side seam that folds over the bottom flap.

Straight Grain Cutting: Cutting the envelope so that the grain runs parallel to the folds.

Substance Weight: A method of measuring paper weight that uses 500 sheets of 17” x 22” paper to establish a basis for the substance weight of a paper type.

Tabbed: A paper tab is placed at specific quantities of envelopes to help with counting for necessary operations.

Tacking: This problem arises when the seal gum is activated too early while it is over the back seams of the envelope.

Throat: This is the open part at the top of the envelope. It is measured from the center of the score line to the top of the back fold.

Thumb Cut: A round cut made into any side of the envelope to help the user remove contents easier.

Tyvek: This is an extremely durable synthetic paper made by DuPont. It is lightweight, tear-proof, and water-proof. It is used for highly confidential documents and heavy or bulky objects.

Wallet Flap: A deep, square-shaped flap.

Wallet Flap Envelope: This envelope uses a wallet flap. It is larger than standard commercial envelopes and is used for heavy mailing needs like bank statements.

Web Cut: A process of manufacturing envelopes where envelope blanks are cut individually. These are typically side seam envelopes.

Window: An opening in the window covered by a patch of film that allows that portion of the envelope’s contents to be seen.


  • OSDS: Open Side, Diagonal Seam
  • OSSS: Open Side, Side Seam
  • BRE: Business Reply Envelope
  • PMS: Pantone Matching System
  • IBM: A commercial envelope of a non-standard size
  • FCGDB: First Class Green Diamond Border
  • FCM: First Class Mailer