Dead Country: A country which no longer issues stamps either because it has ceased to exist or has changed it's name.

Definitive: Regular issue stamps used for ordinary postage and kept in general circulation for a number of years as differentiated from commemoratives which are issued for a relatively short period of time.

Demonetized: A stamp that has been declared no longer postally valid by the issuing authority.

Denomination: The monetary and postal value of a stamp.

Departmental Stamps: Official Government stamps for use by one particular government office.

Design: The printed or engraved portion of the stamp that surrounded by the blank margin.

Die: The piece of metal or other material on which the original engraving of a stamp design is made.

Documentary Stamp: Revenue Stamps used on numerous types of documents such as wills, and mortgages, in payment of a government tax. (Discontinued)

Double Transfer: A stamp showing a second impression of the design distinctly overlapping part or all of the initial impression.

Dry Printing: A printing method in which special inks and greater printing pressure allow for the use of heavier, stiffer paper with a lower moisture content causing the stamp design to stand out more clearly.

Electrotype: A method of producing replicas of a die for printing by applying a coating of copper to a mold taken from the die.

Embossed: Stamps in which part or all of the design is raised above the surface of the paper. Used extensively on pre-stamped envelopes.

Engraving: A method of printing using a metal plate onto which the stamp design has been cut or etched.

Entire: A stamped envelope, postcard, or other postal stationery item, in its entirety as originally sold by the Post Office. (See Cut Squares).

Error Stamp: A stamp with the wrong design, color, printing, paper, perforations, or overprinting. Error stamps because of their relative rarity can be quite valuable.

Expertize: To make an expert examination of a stamp and render an opinion on its genuineness. The American Philatelic Society maintains an Expertizing service.

Face Value: The actual postal value of a stamp as indicated by the figures or words in the design.

First Day Cover: An envelope bearing a cancellation date that represents the first day of issue for that stamp. First Day Covers can be acquired from the issuing Post Office for a period of 30 days after the actual issue date.

First Flight Cover: A cover carried on the inaugural flight of a new airmail route.

Flat Plate: A stamp printing on a press with flat plates as opposed to those printed on a rotary press with curved plates.

Frame: The outer area or border of a stamp design.

Frank: A label or mark indicating that postage has been paid or is free. Most often used on Military Mail issuing from within a war zone.

Fugitive Inks: (Aniline) inks that are used to discourage forgeries and fraudulent erasures. They run when wet and are easily damaged by rubbing

General Collector: A stamp collector who collects all varieties of stamps from different countries. (See Specialist)

Granite Paper: A type of safety paper, with tiny colored fibers running through the paper to deter forgery.

Grill: A network of embossed, raised or indented impressions made in a stamp by a metal roll with points. The grill is said to be points up, if they show on the face of the stamp and face down if they show on the reverse. Grills were used on early US Banknote issues as a method of deterring fraudulent cleaning. There are many different Grill varieties.

Gum: The adhesive coating on the backs of most unused adhesive stamps.

Gutter: The space between panes on a sheet of stamps. (See Sheets & Panes)

Hand-stamped: Stamped or canceled by hand usually with a rubber stamp.

Imperforate: Stamps printed without perforations.

Inconstant: A term used to describe a minor variety which does not appear in the same place on the sheet through multiple printing runs.

Inscription Block: A block of stamps bearing an inscription in the margin relating to the stamps or to general postal matters, such as "Mail Early" or "Use Zip Code".

Intaglio: (Line Engraving) A method of printing where the design is cut into the printing plate and thus is recessed below the surface of the plate.  the ink which collects in the recessed design is then transferred to the paper.  Line Engraved stamps are easily discernible because of the raised ridges on the stamp caused by the ink making up the design.

Interleaves: Translucent tissue on sheets placed between the pages of an album to prevent rubbing. Used in albums were stamps are mounted on both sides of the page.

Invert: A stamp which has part of the design upside down in relation to the rest of the design.

Issue:  A stamp or a related series of stamps, released by a post office department during a certain period of time