Custom Envelope Manufacturer

Custom Envelope Glossary



Envelope Terms - Glossary


Action Device: Intended to generate interaction with the recipient and make them more likely to open the envelope.

Adhesives: Back-gum: Also known as Seam Gum. This is an adhesive that cannot be remoistened. It is used to seal the seams of the envelope to form the envelope pocket.

Latex: Made from a rubber based material for self-seal envelopes. Latex is applied to the seal flap and the back of the envelope, and sticks only to itself.

Peel and Seal: Applied to the seal flap and covered by release paper; self-sealing.

Peerless Tac: A unique closure device designed for long life with repeated opening and closing.

Remoistenable: Adhesive activated by water or solvent. Applied to the seal flap of envelopes.

Resealable:(Latex) A latex adhesive designed to form a lighter bond, this is used for multiple sealing and resealing.



Bang-tail: A style of envelope with a perforated coupon attached to the body of a return envelope. This portion must be torn off before the envelope is sealed. Used for remittance envelopes, order envelopes and other direct

Bar-Code: See POSTNET.

Baronial: A type of envelope recognized by large pointed flap.

Basis Weight: See Substance Weight.

Blank: A die-cut sheet of paper before it is folded into an envelope.

Bleed: An image that extends beyond the edge of the page or envelope.

Blind Emboss: A raised design stamped into paper without foil or ink, must be done before the envelope is folded to prevent the design from debossing onto the back of the envelope.

Bond: A grade of writing or printing papers, often used for letterheads and matching envelopes. Characterized by strength, rigidity, relatively low opacity.

Booklet: A large open side envelope used for catalogs, annual reports or brochures.

Brightness: The light reflecting property of a paper. The more light it reflects, the higher its brightness. A bright sheet offers the best print quality and appearance.

Bulk: Thickness of a sheet of paper in relation to its weight. A high bulk paper lacks compactness; a low bulk paper is compact, with less air space between its fibers. High bulk papers offer a heavier feel to the touch, but a lower mailing weight.

Business Reply Envelopes (BRE): Specially printed envelopes that may be mailed without prepayment of postage. The postage and fees are collected from the permit holder when the mail is delivered back to the sender. Also see FIM and/or PostNet.



Caliper: The thickness of a sheet of paper, measured in units of 1/1000th inch (points or mils).

Catalog: A general term for any large open end envelope.

CD Envelope: A precisely sized envelope to mail, store and protect CDs. Can be made with or without windows or printing in a variety of substrates.

Center Seam: An envelope style where the sides are folded and glued over each other, forming a seam that runs down the center of the envelope.

CI Press: A high speed, high quality 4-color process of flexographic printing.

Clasp: A metal fastener sometimes used with remoistenable gum on booklet and catalog envelopes, allows for repeated opening and closing of the envelope.

Closed Face: An envelope without a window.

Closure: General term used for the means of closing and securing an envelope. May be an adhesive, a clasp or other mechanical closure.

Commercial: General term for the most common style of business envelopes. Open side, with or without windows.

Corner Card: A term used to reference the return address and/or other identification of the sender usually located in the upper left hand corner of an envelope.

Courtesy Reply Envelope (CRE): When a response is desired, such as with a bill or invoice payments, you pay only for the cost of envelopes. Your customer pays the postage, and no permit is required to send CRE mail. You can expedite returns by having pre-addressed and pre-barcoded envelopes.
Also see FIM and/or PostNet.

Credit Card Protector: An open-end or open-side envelope perfectly sized to hold and protect credit cards, phone cards and hotel room keys. Available in paper or Tyvek®.



Deckle Edge: Feathered edge on envelope flap, deliberately produced for decorative purposes.

Diagonal Seam: Seam style frequently used in commercial open-side envelopes and announcement, invitation and baronial envelopes.

Die: A precision tool used to cut out envelope blanks, windows or other shapes.

Double Inside Side Seam: (DISS): Type of seam configuration on open-side envelopes where seams tuck beneath back panel.

Double Outside Side Seam: (DOSS): Seam configuration on open-side envelopes where seams are glued on top of back panel.

Drive-Up: (Also called Teller-Helper envelope.) Used frequently by financial institutions to return cash to customers at counters and drive-up windows.

Dummy: An unprinted mock-up of a “to-be-printed” piece. A dummy serves as a reference for the client, printer, mailing house, or distributor.



Embossed Finish: A raised pattern applied to paper.

Expansion Envelope: Envelope with a gusset or box bottom and sides, allowing it to expand for bulky mailings.

Eyelet: Small hole in a tag or envelope to receive a string or clasp. May be plain or reinforced with a metal ring, paper or cloth backing.



Face: The side of the envelope without seams.

FIM: (Facing Identification Mark) A pattern of vertical bars printed in the upper right portion of the envelope. Used to identify BRE (has 6 vertical bars) and CRE (has 5 vertical bars) envelopes. These marks are used by the Post Office for automated facing and canceling equipment.

Finish: The surface properties of a paper, including smoothness or textured, coated or uncoated, soft or hard. Different finishes offer different printing characteristics.

First Class Envelope: A catalog style (open-end) envelope printed with green “First Class” around the edges.

Flaps Extended: A term used to describe the packing of envelopes with seal flap in an unfolded position.

Full View: A Full View envelope has an extra large window designed to give maximum exposure to the contents. Especially valuable for attracting attention and enhancing response to direct mail advertising.



Glassine: A smooth, dense semi-transparent paper. Sometimes used as window patch material.

Grain: Direction in which most of the fibers lie in a finished sheet of paper. Paper folds more easily with the grain. It offers greater resistance to being torn across the grain, and demonstrates greater tensile strength in the direction of the grain.

Gum: See Adhesives.



Insert Size: As a rule of thumb, envelopes should be one half inch wider and one fourth inch higher than the largest piece to be inserted. Automatic inserting equipment may require more space.

Inside Tint: A printed design on the inside of the envelope used for added opacity and/ or security. Available in stock or custom designs. See page 15 for available tints.

Interoffice Envelope: An open-end envelope designed for multiple-use routing of internal communications. Available with a variety of closures including clasp, string-and-button, and tamper evident peerless tact.



Kraft: Paper grade made from unbleached, bleached or colored wood pulp by the sulfate process. Kraft papers have a coarser finish than woves and are noted for their strength.



Laid: Type of finish, characterized by a closely “lined appearance”.

Latex: See Adhesives, Resealable.

Lip: Unscored, extended flap on some open-side envelopes, such as those used for filing.



Manila: A semi-bleached chemical sulfate paper. Not as strong as Kraft, but with better printing qualities.

Mock-Up: See Dummy.


Nest-End: Term referring to packing of envelopes where they are nesting together with flaps extended. Flap is scored, closed and then re-opened before packing. Eliminates “handflapping”.



Offset Paper: General description of any paper primarily suited for offset printing. Can be coated or uncoated. Characterized by strength, dimensional stability, lack of curl and freedom from foreign surface material. Finish can be vellum or smooth.

Opacity: Paper property that measures the degree to which paper stops light from passing through. Inside tints can be used to compensate for low-opacity papers.

Open-End: Style of envelope in which the opening is on the shorter side. See Catalog Page 7.

Open-Side: Style of envelope in which the opening is on the longer side. See Booklet Page 6.



Patch Material: Refers to the material used to cover envelope windows. Can be translucent or clear. Materials are poly, cello and glassine. An envelope with a window but containing no patch material is referred to as an “open window”.

Pictorial: See Full View.

Polystyrene: A thermoplastic material used for window patch.

POSTNET: (POSTal Numeric Encoding Technique) This is the barcode used to encode ZIP Code information letter mail for rapid and reliable sorting by barcode sorters (BCS’s). To receive automation discounts, letter-size mail must be 100-percent delivery point bar coded and meet addressing, readability, and other requirements for processing on automated equipment. Used on BRE and CRE mail.

Printing: The choice of a printing process depends upon several factors. Some of which include the quantity, complexity and characteristics of the artwork, number of ink colors, as well as the paper stock and the level of desired quality of the finished product.

Flexography: (Also called FLEXO printing) A form of rotary letterpress using flexible rubber or photopolymer plates. Most common type of envelope printing, fast drying process, suitable for screens with 65105 lines. Printed in line at the same time envelope is converted. The art is lower imagery art. Generally the most cost effective price for larger quantities.

Jet Printing: Prints converted envelopes; equipment varies from 1 to 4 colors, 1 or 2-sided. Allows for fast turn times, good quality, and medium pricing.

Lithography: (Also know as FLAT SHEET LITHO or OFFSET PRINTING) Offers highest degree of precision, clarity and quality, uses screens of 133 lines or more. Artwork with full bleeds requires flat sheet lithography. Highest quality, top of price range.

Proxy: A booklet style envelope used to mail an annual report and a proxy statement. Contains a special pocket for the proxy.



Ream: 500 sheets of paper.



Self-Seal Latex: See Adhesives, Resealable.

Shelf Life: The length of time after manufacturing that a product will remain in a saleable or acceptable condition.

Side Seam Inside: Single seam construction on open-end envelopes, where seam glues beneath back panel. Allows full printing on back of envelopes. Can be on left or right side. (LISS or RISS).

Side Seam Outside: Single side seam construction on open-end envelopes, where seam is glued on top of back panel. Can be right of left side. (ROSS, LOSS).

Split Seal Gum: Gum pattern on seal flap when envelopes are to be used on automatic inserting equipment. Gum is broken where flap covers envelope at seams; prevents flap from sticking to the back panel during storage in humid climates.

String-and-Button: Mechanical closure with a string attached to the flap and a button on the body of the envelope.

Substance Weight: (Also called Basis Weight) Weight, measured in pounds, of a ream (500 sheets) of paper in its basic size. Different grades of paper are sold in different basic sizes. Therefore, basis weights of different grades of paper can not be compared directly; a 24# white wove (WW) is comparable to a 60# offset, NOT a 24# offset.

Standard Substance Weights-Wove:

16 lb. Used for overseas air mail envelopes.

20 lb. Used for commercial envelopes where strength & opacity is not a factor.

24 lb. Workhorse of envelope papers-used for most open-side official and commercial envelopes.

28 lb. Used for most open-end and catalog envelopes and larger size commercial envelopes.

32 lb. Used for heavy duty envelopes and clasp envelopes.

40 lb. Used for large envelopes, heavy duty envelopes or envelopes used for frequent re-use.



Teller-Helper: See Drive-Up.

Text: Type of high quality paper, manufactured in white or colors from bleached chemical wood pulp and/or cotton fibers. Manufactured in a wide variety of finishes, including antique, vellum, smooth, felt-marked and embossed. Often has matching cover stock. In envelopes, most often used for annual reports, brochures or other prestige mailings where an envelope that matches or complements the enclosure is desired.

Thumb Cut: Found on envelopes manufactured without flaps, such as filing and film storage. Can be cut on one side or double thumb cut, for easier extraction of contents.

Top: When referring to the envelope specifications, the dimension of the envelope with the opening, even if it is on the “side” relative to the address, corner card, etc.

Tuck Flap: Flap with no gum, used primarily on interoffice and other reusable envelopes.

Tyvek®: Spun bonded olefin product manufactured by DuPont. Offers maximum protection and durability at a very light weight. Tyvek® is unaffected by moisture and inert to most chemicals. Acid, lint and sulfide free.



Window: A cut-out in the body of the envelope positioned to show mailing address, return address and/or special messages. Eliminates the duplication of efforts and the potential for error in addressing envelopes. Customized windows can be created in the shape of product or logo. Usually covered with a transparent window patch material. Can be left open with no patch, except in Canada.

Window Position: Location of the window on the envelope, as measured from the left and bottom edges of the envelope. Window edge should be no closer than 3/8” from the side (to allow space for gluing window material) and 5/8” from the bottom (to correspond to current postal recommendations) of a standard commercial envelope. Other sizes and styles vary. Postal recommendations and regulations are subject to change.

Wove: Paper having uniform surface and no discernible marks. Soft, smooth finish. Most widely used envelope paper. Lower in opacity, brightness and bulk. Available in white or colors.

Note: Envelope and window dimensions are always indicated with the height dimension listed first and the width dimension listed second.