C.D.S: A circular date stamp used for cancelling the stamp by the postal authorities.
Cachet: A special endorsement or commemorative description on a cover. In philately special postmarks used in exhibitions or occasional flights connected with Rocket mail, Helicopter mail, modern first-day covers, special-event covers etc. are documented with hand stamp or cachets.
Canceled-to-order – (CTO): Stamps which are cancelled by the postal authorities without being sent through post, usually in full sheets, The cancels may be printed on the stamps at the same time that the stamp design is printed. A stamp with a cancel and with full gum is likely a CTO stamp, CTO stamps are sold to stamp dealers at large discounts from face value. Most catalogs say whether they price CTO stamps or genuinely used stamps.
Cancellation: The marking used by the receiving post office of a letter with hand struck marking to show that the stamp has been used and is no longer valid. Modern cancels usually include the name of the original mailing location or a nearby sorting facility and the date of mailing. Most cancellations also include a section of lines, bars, text or a design that print upon the postage stamp to invalid it, machine or hand struck obliteration or piercing or punching with holes, even the removal of a portion of the stamp. Also known as cancel.
Cancelled by Compliance: Stamps cancelled on request to oblige collectors.
Cancelled by Favour: This can involve regular or special cancellations and is generally connected with the philatelic requests for first day covers or other postmarks of significance.
Cantonal stamps: Issues of Switzerland’s cantons (states) used before the release of national stamps. The cantonal issues of Basel (1845), Geneva (1843-50) and Zurich (1843-50) are among the classics of philately.
Cape Triangles: Common name for the triangular Cape of Good Hope stamps of 1853-64, the first stamps printed in triangular format. The distinctive shape helped illiterate postal clerks distinguish letters originating in the colony from those from other colonies.
Cartes Maxim: The name for Maxim cared collection.
Catalog value: The list at which stamps can be purchased from publishers, Some catalogs list stamps at a retail value, though actual dealer prices may vary substantially for reasons of condition, demand or other market factors. Most catalogs have a set minimum value for the most common stamps.
Catalog: A comprehensive book or similar compilation with descriptive information to help identify stamps. A catalog contains the date issue, size, perforation, colour, details about design, watermark, errors, prices at which generally sold etc. Many catalogs include values for the listed items. An auction catalog is published by the auction firm in advance of a planned sale to notify potential customers of the specific items that will be offered.
Censored mail: A cover bearing a hand stamp or label indicating that the envelope has been opened and the contents inspected by a censor.
Centering: The relative position of the design of a stamp in relation to its margins. Assuming that a stamp is undamaged, centering is generally a very important factor in determining grade and value.
Certified mail: A service of most postal administrations that provides proof of mailing and delivery without indemnity for loss or damage.
Chalky paper: A chalk-surfaced paper for printing stamps. Any attempt to remove the cancel on a used chalky-paper stamp will also remove the design. Immersion of such stamps in water will cause the design to lift off. Touching chalky paper with silver will leave a discernible, pencil-like mark and is a means of distinguishing chalky paper.
Changeling: A stamp whose color has been changed-intentionally or unintentionally-by contact with a chemical or exposure to light.
Charity seals: Stamp like labels that are distributed by a charity. They have no postal validity, although they are often affixed to envelopes. United States Christmas seals are one example.
Charity stamp: A stamp sold at a price greater than postal value, with the additional charge dedicated for a special purpose. Usually recognized by the presence of two (often different) values, separated by a “+” sign, on a single stamp.
Cinderella: A stamp like label that is not a postage stamp. Cinderella include seals and bogus issues, as well as revenue stamps, local post issues and other similar items.
Classic: An early issue, often with a connotation of rarity, although classic stamps are not necessarily rare. A particularly scarce recent item may be referred to as a modern classic.
Cleaning (stamps): Soiled or stained stamps are sometimes cleaned with chemicals or by erasing. The cleaning is usually done to improve the appearance of a stamp. A cleaned stamp can also mean one from which a cancellation has been removed, making a used stamp appear unused.
Cliché: The individual unit consisting of the design of a single stamp, combined with others to make up the complete printing plate. Individual designs on modern one-piece printing plates are referred to as subjects.
Coil: Stamps processed in a long single row and prepared for sale in rolls, often for dispensing from stamp-vending and affixing machines. Some coils, including most U.S. coils, have a straight edge on two parallel sides and perforations on the remaining two parallel sides. Some coils are backprinted with sequence or counting numbers.
Collateral material: Any supportive or explanatory material relating to a given stamp or philatelic topic. The material may be either directly postal in nature (post office news releases, rate schedules, souvenir cards, promotional items) or nonpostal (maps, photos of scenes appearing on stamps).
Colour Shift: Where the design of the stamp has more than one colour and these are applied at different times in the process of printing and the positioning of the colours is incorrect in relation to the intended design.
Comb Perforation: The perforations of a stamp formed by the pins of the perforating machine which are arranged like a comb.
Combination cover: Cover bearing the stamps of more than one country when separate postal charges are paid for the transport of a cover by each country. Also stamps of the same country canceled at two different times on the same cover as a souvenir.
Commatology: Specialized collecting of postmarks. This term was invented before World War II to describe postmark collecting. It is rarely used. Usually, collectors refer to postmark collecting or marcophily.
Commemorative: A stamp printed in a limited quantity and available for purchase for a limited time. The design may note an anniversary associated with an individual, an historic event, or a national landmark.
Compound perforations: Different gauge perforations on different sides of a single stamp. The sides with the different gauge measurements are usually perpendicular.
Condition: The overall appearance and soundness of a stamp or cover. Positive condition factors include fresh full color, full original gum on unused stamps, and so on. Damage such as creases, tears, thinned paper, short perforation teeth, toning and so on negatively affect condition.
Condominium: A Territory over which there is joint rule by two Powers. An example of this is the Anglo – French New Hebrides Condominium whose stamps are inscribed in English and French.
Controlled mail: A system in which the mailer selects philatelically desirable issues for outgoing mail, arranges for a specific manner of cancellation and secures the stamps’ return by the addressee. In some cases such controlled mail operations may provide rare examples of specific rate fulfillment, or other similar postal use.
Copyright block: Block of four or more United States stamps with the copyright notice marginal marking of the United States Postal Service. The copyright marking was introduced in 1978 and replaced the Mail Early marking.
Corner card: An imprinted return address, generally in the upper-left corner of an envelope, from a commercial, institutional or private source, similar to business card or letterhead imprints.
Counterfeit: Any stamp, cancellation or cover created for deception or imitation, intended to be accepted by others as genuine. A counterfeit stamp is designed to deceive postal authorities.
Cover: An envelope or piece of postal stationery, usually one that has been mailed. Folded letters that were addressed and mailed without an envelope and the wrappers from mailed parcels are also covers.
Crash cover: A cover that has been salvaged from the crash of an airplane, train, ship or other vehicle. Such covers often carry a postal marking explaining damage or delay in delivery.
Crease: A noticeable weakening of the paper of a stamp or cover, caused by its being folded or bent at some point. Creases substantially lower a stamp’s value. Creases particularly affect cover values when they extend through the attached stamp or a postal marking. Stamp creases are visible in watermark fluid.
CTO or Canceled-to-order: Stamps are “canceled to order,” usually in full sheets, by many governments. The cancels may be printed on the stamps at the same time that the stamp design is printed. A stamp with a cancel and with full gum is likely a CTO stamp, as CTOs do not see actual postal use. CTO stamps are sold to stamp dealers at large discounts from face value. Most catalogs say whether they price CTO stamps or genuinely used stamps.
Cut cancellation: A cancellation that intentionally slices into the stamp paper. Often a wedge-shaped section is cut away. On many issues, such cancellations indicate use of postage stamps as fiscals (revenues) or telegraph stamps rather than as postage. Cut cancellations were used experimentally on early United States postage stamps to prevent reuse.
Cut square: A neatly trimmed rectangular or square section from a stamped envelope that includes the imprinted postage stamp with ample margin. Collectors generally prefer to collect stationery as entire pieces rather than as cut squares. Some older stationery is available only in cut squares.
Cut-to-shape: A nonrectangular stamp or postal stationery imprint cut to the shape of the design, rather than cut square. Cut-to-shape stamps and stationery generally have lower value than those cut square. One of the world’s most valuable stamps, the unique 1856 British Guiana “Penny Magenta” is a cut-to-shape stamp.
Cylinder Number: The number in the margins of a sheet of stamps which identifies the cylinder which has been used in the production process.
Cylinder: A curved printing plate used on a modern rotary press. The plate has no seams.