SASE: A self-addressed, stamped envelope. An unused envelope bearing the address of the sender and sufficient return postage. Enclosed with correspondence to make answering easy.
Secret mark: A minute alteration to a stamp design added to distinguish later printings from earlier printings by a different firm. Secret marks may positively distinguish genuine stamps from counterfeits.
Seebeck: The nickname for various Latin American issues produced 1890-99 in contract with Nicholas Frederick Seebeck, the agent for the Hamilton Bank Note Co. of New York. Seebeck agreed to provide new issues of stamps and stationery each year at no charge, in return for the right to sell remainders and reprints to collectors. The resulting furor destroyed Seebeck and blackened the philatelic reputations of the countries involved.
Self-adhesive: Stamp gum that adheres to envelope paper by the application of pressure alone. Most self-adhesive stamps are sold on a coated paper release liner. See also Liner, Linerless, Water-activated.
Selvage: The marginal paper on a sheet or pane of stamps. Selvage may be unprinted or may contain printer’s markings or other information.
Semipostal: 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.
Series: A group of stamps with a similar design or theme, issued over a period of time. A series may be planned or may evolve.
Service inscribed: A stamp with wording as part of the initial printed design that identifies the mail-handling service for which the stamp is intended, such as “Presorted First-Class.”
Set: Stamps sharing common design elements, often issued at one time and usually collected as a group.
Se-tenant: French for “joined together.” Two or more unseparated stamps of different designs, colors, denominations or types.
Shade: The minor variation commonly found in any basic color. Shades may be accorded catalog status when they are very distinctive.
Sheet: A complete unit of stamps as printed. Stamps are usually printed in large sheets and are separated into two or more panes before shipment to post offices.
Ship letter: Mail carried by private ship.
Short set: An incomplete set of stamps, usually lacking either the high value or one or more key values.
Sleeper: Stamp or other collectible item that seems to be underpriced and may have good investment potential.
Sleeve: 1) A seamless cylindrical printing plate used in rotary intaglio printing. 2) A flat transparent holder, often specifically for protecting and storing a cover.
Soaking: Removal of stamps from envelope paper. Most stamps may be safely soaked in water. Fugitive inks, however, will run in water, and chalky-surfaced papers will lose their designs entirely, so some knowledge of stamps is a necessity. Colored envelope paper should be soaked separately.
Souvenir card: A philatelic card, not valid for postage, issued in conjunction with some special event. The souvenir card often illustrates the design of a postage stamp.
Souvenir page: An announcement of a new United States stamp issue created by the U.S. Postal Service, bearing a copy of the new stamp tied by a first day of issue cancellation.
Souvenir sheet: A small sheet of stamps, including one value or a set of stamps. A souvenir sheet usually has a wide margin and an inscription describing an event being commemorated. Stamps on a souvenir sheet may be perforated or imperforate.
Space filler: A stamp in poor condition used to fill the designated space in a stamp album until a better copy can be found.
Special delivery: A service providing expedited delivery of mail. Called Express by some nations.
Special handling: A U.S. service providing expeditious handling for fourth-class material.
Special printing: Reissue of a stamp of current or recent design, often with distinctive color, paper or perforations.
Special stamps: Regular postage stamp issues that fall outside the traditional definitions of commemorative and definitive stamps.
Specialist: A stamp collector who intensively studies and collects the stamps and postal history of a given country, area, or time period, or who has otherwise limited his collecting field.
Specimen: Stamp or stationery item distributed to Universal Postal Union members for identification purposes and to the philatelic press and trade for publicity purposes. Specimens are overprinted or punched with the word “SPECIMEN” or its equivalent, or are overprinted or punched in a way to make them different from the issued stamps. Specimens of scarce stamps tend to be less valuable than the actual stamps. Specimens of relatively common stamps are more valuable.
Speculative issue: A stamp or issue released primarily for sale to collectors, rather than to meet any legitimate postal need.
Splice: The repair of a break in a roll of stamp paper, or the joining of two rolls of paper for continuous printing. Stamps printed over a splice are usually removed and destroyed before the normal stamps are issued.
Stamp: An officially issued postage label, often adhesive, attesting that payment has been rendered for mail delivery. Initially used as a verb, meaning to imprint or impress; as in, to stamp a design.
Stampless cover: A folded sheet or envelope carried as mail without a postage stamp. This term usually refers to covers predating the requirement that stamps be affixed to all letters.
Stock book: A specially manufactured blank book containing rows of pockets on each page to hold stamps.
Straight edge: Flat-plate or rotary-plate stamps from the margins of panes where the sheets were cut apart. Straight-edge stamps have no perforations on one or two adjacent sides. Sometimes straight-edge stamps show a guideline.
Strip: Three or more unseparated stamps in a row, vertically or horizontally.
Surcharge: An overprint that changes or restates the denomination of a stamp or postal stationery item.
Surface-colored paper: Paper colored on the surface only, with a white or uncolored back.
Surtax: The portion of a semipostal stamp purchase price exceeding the postage value. The surtax is designated for donation to a charity or some other purpose.
Sweatbox: A closed box containing dampened spongelike material, over which stuck-together unused stamps are placed on a grill. Humidity softens the gum, allowing separation of stamps. In some cases, the sweatbox may be used to help remove a postally used stamp from envelope paper.