#	Term	Definition
1	Adhesive	The substance on the back of a stamp that allows it to attach to an envelope or postcard.
2	Airmail Stamp	A stamp that prepayed the postal rates for air transport.
3	Album	Used by collectors to store stamps, usually in some ordered format.
4	Block	A series of attached stamps at least two high and two wide.
5	Booklet Pane	A section of stamps from a stamp booklet.  This is a whole section (or page), untorn but unattached to the full booklet.
6	Cancellation	A mark used by the post office to indicate that a stamp has paid for services and cannot be reused.  Some cancellations are blobs or blotches while others can have significant meaning.
7	Centering	The position of the design of a stamp between the edges.  A perfectly centered stamp will have equal spaces between the perforations (or edges) and the border of the design.
8	Coil	Stamps are sometimes sold in coils.  These stamps usually have two imperforate (straight) edges.  These straight edges are usually on the top and the bottom of the stamp.
9	Coil Pair	A pair of coil stamps still together.  Many collectors like to collect pairs from a coil.
10	Commemoratives	Stamps that are issued for a limited time and are in honor or celebration of specific people or events.
11	Condition	The condition of a stamp is determined by a variety of factors.  It can be cancelled or uncancelled, has adhesive or not, been hinged or not, physical condition of the stamp, centering, etc.
12	Cover	An envelope with a postage stamp affixed.
13	Curved Plate	A cylindrical plate used in rotary style printing presses.  Due to the method of printing, images are slightly distorted.
14	Definitives	These are usually smaller sized stamps that are printed in large quantities.  They are often a single color and are made available for an indefinite period of time.
15	Denomination	The monetary value that a stamp will pay for in delivering a package or letter.  Its face value.
16	Face Value	The amount of money that a stamp costs where purchased new.  The demonination.
17	Facing	Vertical bars read by automated equipment that can identify, orient and separates different classes of mail.
18	FIPEX	Fifth International Philatelic Exhibition.  The Fifth International Philatelic Exhibition was in New York City on April 28 through May 5, 1956.
19	First Day Cover	A cover (envelope) with a stamp affixed that is cancelled on the first day it was issued.  Many of these have special cancellations related to the stamp.
20	Flat Plate	A metal plate used in printing presses.
21	Gum	A term for the adhesive on the back of a stamp that attaches the stamp to an envelope or package.
22	Gum Breakers	Breaks in the gumming on stamps that reduce the amount of curling a sheet has when printed on a rotary press.  There are three kinds of Gum Breakers - Type I the breaks are 5.5mm apart, Type II the breaks are 22mm and on Type III they are 12mm apart.
23	Gutter Block	A block of stamps separated by a gutter.
24	Gutter Margin	Gutter margin is a margin dividing a sheet of stamps into separate panes.
25	Gutter Pair	A pair of stamps separated by a gutter.
26	Hinge	A small piece of gummed paper that is used to affix a stamp to a stamp album without using the stamps adhesive to do so.  This allows for stamps to be more easily removed if necessary.  Using hinges on mint stamps does some damage to the gum on the stamp.
27	Imperforate	A stamp that has no perforations (the small holes between stamps that allow for easy separation of the stamps).
28	Line Pair	A coil pair in which a line is shown through the perforations.  A guide line pair has deliberate lines in the plate and are generally very clear.  A joint line pair is caused from the seam in the cylindrical plate when printing and are less distinct.
29	Lithography	The lithography printing method relies on a flat surface where the image areas attract oil-based ink and non-image areas repel it based on oil/water repulsion.  The result is smooth and continuous ink coverage with sharp clean edges.  This is most noticeable on vertical or horizontal lines and on numeral values.  There are no visible dots or texture under magnification, and the surface feels flat.
30	Meta Series	This is my term for a stamp series that spans many years and many variations.  More a like a theme than a series, such as Love or Statehood stamps.
31	Mint	A stamp that is in the same condition as it was when first printed.  This means, among other things, that it has never been hinged and has all of it gum.
32	Overprint	Printing on a stamp that was not part of the original design.  Overprints may occur when there is not enough time to print new stamps for whatever purpose the stamp is needed.  In these cases existing stamps are overstamped.  Precancelled stamps are also an example of an overprint.
33	Pane	A full sheet of stamps.
34	Perfins	Perfin is a contraction of perforated initials or perforated insignia.  These are stamps that have been punched with initials, letters, or symbols after they were issued, usually to identify an organization or individual that used them.
35	Perforations	The small holes punched between stamps that allows them to be separated easily.  Perforations come in styles and in differing widths and may vary even for the same stamp design.
36	Philately	The hobby of stamp collecting and the study of stamps.
37	Photogravure	The photogravure printing method uses an etched metal cylinder with recessed areas that hold ink.  The image is created by transferring a design to a gelatin-coated plate which is chemically etched to form varying depths of recesses.  This results in a speckled or mottled appearance under magnification, especially in solid areas, and ragged or uneven edges where different colors meet.  The surface feels slightly two-dimensional.
38	Plate Block	A block of stamps that includes a plate number on the selvage which identifies the plate used during printing.
39	Postage Due	A type of stamp that indicates there was not enough postage to deliver the letter.  The receiver then pays the additional postage shown.
40	Postal Stationary	Some form of letter or postcard that has postage payment pre-marked on it and therefore does not require a stamp.
41	Postmark	A mark indicating from where the letter was sent.  Usually used as part of the cancellation.
42	Precancelled	Precancelled letters are primarily used for bulk mailers in order to reduce processing time.
43	Prexies	A nickname given to the Presidential defiinitives series issued 1938-1954.
44	Selvage	The margin of a pane of stamps.  This may include plate numbers and other markings.  Individual stamps or blocks may have selvage attached also.
45	Semi-postal	Postage stamps are sold for more than their postage value in order to raise funds for a charity.
46	Se-tenant	Two or more stamps that are attached but are of different designs.
47	Souvenir Sheet	Sheets of stamps that are issued primarily for collecting purposes.  These will usually have some form of decorative border and additional information included.
48	Special	Specials are usually similar to definitives but are issued for special occasions or themes.  The Love stamps and the Christmas stamps are examples.
49	Thematic	Stamps that share a similar design and theme such as national parks, animals, space exploration, etc.  These are sometimes issued on the same page or souvenir sheets together.
50	Tongs	Tweezers usually with a flat smooth gripping service that are used to handle stamps so that finger grease and prints don't mar them.