SE TENANT.--A French expression signifying that the stamps referred to have not been separated: usually employed in reference to an error, or variety, when still forming a pair with a normal stamp. SERPENTINE ROULETTE.--_See_ PERCÉ EN SERPENTIN. SHEET (OF PAPER).--There are three "sheets": a mill-sheet, as manufactured; a sheet as printed, which may be, and often is, less than a mill-sheet; and a "post-office" sheet, either the whole or an arbitrary part of a printed sheet, so divided for convenience of reckoning. SILK-THREAD PAPER.--_See_ PAPER (DICKINSON). SINGLE-LINE PERFORATION.--_See_ GUILLOTINE. SPANDREL is the term for the triangular space between a circle, oval, or curve, and the rectangular frame enclosing it. SPECIALISING.--To develop in a collection a complete record of the inception, history, and use of the stamps of a particular country, or group of countries, in the fullest and most detailed manner. In contradistinction to GENERALISING (which see). STATIONERY.--_See_ ENTIRES. STEREOTYPE OR STEREO.--A reproduction of the original design, made by means of a _papier-maché_ or other mould, in type-metal. And see MATRIX. STRIP is the philatelic term for three or more stamps unsevered and in the same row, horizontal or vertical. SURCHARGE.--An overprint (which see) which alters the face value of a stamp, or confirms it in the same or a new currency. The term is loosely used to mean any overprint, but it is desirable that its application be confined to inscriptions affecting the denomination of face-value. SURFACE-PRINTED, that is, printed by a process in which the parts of the plate, &c., which produce the coloured portions of the stamp are raised up. _See_ PRINTING. TAILLE DOUCE.--When a design is cut into the substance of the plate it is said to be engraved in TAILLE DOUCE. A familiar example is a visiting-card plate. TÊTE-BÊCHE is a French expression signifying the inversion of one stamp of a pair (or more) in relation to the other stamp (or stamps): naturally, the peculiarity disappears on severance, and such varieties must necessarily be in a pair or more. TONED, as applied to paper, implies a very slight buff tint. TRESSE.--_See_ ROSACE. TRIALS.--These are impressions from die, plate, stone, &c., taken to ascertain if the design be correct, or to assist in the selection of a suitable colour. [Illustration: EXAMPLES OF SOME PHILATELIC TERMS. Photograph of a flat steel _die_ engraved in _taille douce_ (_i.e._, with the lines of the design cut into the plate). The stamp is the 50 lepta of Greece, issue of 1901, showing Hermes adapted from the Mercury of Giovanni da Bologna.] TYPE.--A representative common design, as distinguished from "VARIETY," which indicates slight deviations therefrom.