A signature mark is a letter, number or combination of either or both, which is printed at the bottom of the first page, or leaf, of a signature or section. This practise is to ensure that the bookbinder can order the pages and sections in the correct order.

Contemporary use of signature marks

A number of symbols used as binding signature marks were encoded in ISO 5426-2 and from there (to enable migration of data from the old standard) found their way into Unicode

Unicode

Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...

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• 0x32 REFERENCE MARK was unified with U+203B (※)
• 0x34 MALTESE CROSS, with U+2720 (✠)
• 0x36 RIGHTWARDS LEAF ARROW, with U+2767 (❧) ROTATED FLORAL HEART BULLET (= hedera, ivy leaf)
• 0x37 LATIN CAPITAL LETTER SIDEWAYS Q had to be added into Unicode as U+213A (℺), ROTATED CAPITAL Q

U+2619 (☙), REVERSED ROTATED FLORAL HEART BULLET, was added later. These latter two are the only codepoints in Unicode 4.0 to bear the annotation "binding signature mark". It is unlikely that Unicode will encode any more marks since they constitute metatextual and not textual information even though other symbols were used as binding signature marks with printer

Printer

Printer may refer to:* Printer , a person or a company* Printer , a hardware device* Optical printer for motion picture films* The Moscow subway station Pechatniki, whose name means "Printers"...

s making something of a house style of the particular blocks of type they chose.