Catalogs & numbering
Scott numbers
The catalog numbers assigned by the Scott catalog, the standard way US collectors and dealers name an exact stamp and variety (for example Scott 1 or C3a).
Read the guideStamp collecting glossary
Stamp collecting terms, explained
Short, plain-English definitions of the words collectors and dealers use, from Scott numbers to grills. The main terms link to a full guide with examples, the details that change value, and sources.
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Condition
Mint vs. used stamps
Mint stamps are unused with their original gum; used stamps have been through the mail and cancelled. Collectors split mint into never hinged (MNH), hinged (MH) and no gum, and treat cancelled-to-order (CTO) stamps separately.
Read the guideThe hobby
Philately
The study and collecting of postage stamps and postal history. Someone who practices it is a philatelist, the formal name for a stamp collector.
Read the guideGlossary A–Z
C
- Cachet
- Any printed or drawn design on a cover, usually on the left side of the envelope. Most often seen on first day covers. Read more
- Cancellation
- The postal marking that defaces a stamp so it can't be reused. The postmark is the part showing date and place. The type and neatness of a cancel can raise or lower value. Full guide
- Cancelled to order (CTO)
- A stamp cancelled by the postal service without going through the mail, usually with a neat corner cancel and full gum. Worth far less than postally used. Read more
F
- First day cover
- An envelope or card with a new stamp postmarked on its first day of issue, usually with a printed design called a cachet. Most made since the 1950s are worth little. Full guide
G
- Grill
- A waffle-like pattern of points embossed into US stamps from 1867 into the 1870s so cancelling ink would soak in. The grill type decides the Scott number; only two 1¢ Z grill stamps are known. Full guide
I
- Imperforate
- A stamp issued without perforations, which has to be cut from the sheet. Read more
K
M
- Manuscript cancel
- A cancellation made by pen or marker. On early US stamps it lowers value considerably. Read more
- Mint never hinged (MNH)
- A mint stamp whose gum has never been disturbed by a hinge. Read more
- Mint vs. used stamps
- Mint stamps are unused with their original gum; used stamps have been through the mail and cancelled. Collectors split mint into never hinged (MNH), hinged (MH) and no gum, and treat cancelled-to-order (CTO) stamps separately. Full guide
O
- Overprint
- Extra text or a design printed over an existing stamp, for example to change its value (a surcharge), mark it for a territory or deter theft. Valuable overprints are frequently faked. Full guide
P
- Perforations
- The rows of small holes between stamps that let them be torn apart. The perforation gauge counts holes per 2 centimeters, and a half-hole difference can separate a common stamp from a rare one. Full guide
- Philately
- The study and collecting of postage stamps and postal history. Someone who practices it is a philatelist, the formal name for a stamp collector. Full guide
- Plate block
- A block of stamps from the sheet margin that includes the printing plate number. US plate blocks were traditionally four or six stamps; coil stamps with plate numbers are collected as plate number coils (PNCs). Full guide
- Plate number coil (PNC)
- A US coil stamp with the printing plate number printed on it, collected in strips of three or five. The first was the 18¢ Flag of 1981. Read more
R
- Rouletting
- Separation made with small cuts in the paper instead of punched holes. Read more
S
- Scott numbers
- The catalog numbers assigned by the Scott catalog, the standard way US collectors and dealers name an exact stamp and variety (for example Scott 1 or C3a). Full guide
- Semi-postal
- A stamp sold for more than its face value, with part of the difference donated to a named cause. Scott numbers start with B. Read more
- Silkote paper
- A very white, smooth paper the Bureau of Engraving and Printing used experimentally for a small number of 2¢ Jefferson sheet stamps. Read more
- Socked on the nose (SON)
- A circular cancellation struck squarely in the center of a stamp. Read more
- Souvenir sheet
- A small sheet of one or more stamps with an inscribed or decorated margin, usually issued for a stamp exhibition or anniversary. The first US one was the 1926 White Plains sheet. Full guide
- Special delivery
- A fee-based service that delivered an item immediately on arrival at the destination post office. US special delivery stamps have Scott numbers starting with E. Read more
- Stamp hinges and mounts
- Hinges are small folded strips of gummed glassine for fixing stamps to album pages; mounts are clear plastic holders that keep a stamp in place without touching its gum. Full guide
- Stock book
- A book with clear strips on each page that form pockets for storing stamps without hinges. Read more
W
- Watermarks
- A pattern pressed into stamp paper during manufacture, seen as a thinner area when the stamp is placed face down in watermark fluid. On many classic stamps it decides which catalog number applies. Full guide
Check the details yourself
Perforations, watermarks and centering are the details that separate a common stamp from a scarce variety of the same design. These free tools help you check them.
Sources & References
- FDC Terminology - American First Day Cover Society
- Cancellation (mail) - Wikipedia
- Glossary of Stamp Terms - Mystic Stamp Company
- A Glossary of Terms for the Collector of United States Stamps - United States Stamp Society
- Postage stamp separation - Wikipedia
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