ISO 15924

ISO 15924, Codes for the representation of names of scripts, defines two sets of codes for a number of writing systems (scripts). Each script is given both a four-letter code and a numeric one. Script is defined as "set of graphic characters used for the written form of one or more languages".

Where possible the codes are derived from ISO 639-2 where the name of a script and the name of a language using the script are identical (example: Gujarātī ISO 639 guj, ISO 15924 Gujr). Preference is given to the 639-2 Bibliographical codes, which is different from the otherwise often favored use of the Terminological codes.

4-letter ISO 15924 codes are incorporated into the Language Subtag Registry for IETF language tags and so can be used in file formats that make use of such language tags. For example, they can be used in HTML and XML to help Web browsers determine which typeface to use for foreign text. This way one could differentiate, for example, between Serbian written in the Cyrillic or Latin  script, or mark romanized text as such.

Maintenance
ISO has appointed the Unicode Consortium as the Registration Authority (RA) for the standard. In 2004, the RA appointed Michael Everson to act as Registrar. The Registrar works with a Joint Advisory Committee (JAC) in developing and implementing the standard. The JAC contains six members: the Registrar, 1 member from the Library of Congress, 1 from Standards Norway, 1 from the French Encyclopaedia Universalis, an officer of Unicode, and a member of Unicode. These individuals represent the interests of the ISO 15924 RA, the ISO 639-2 RA, ISO Technical Committee 37, ISO Technical Committee 46, and the ISO Coded Character Set Sub-Committee, ISO/IEC JTC1/SC2.

Numeric ranges

 * 000–099 Hieroglyphic and cuneiform scripts
 * 100–199 Right-to-left alphabetic scripts
 * 200–299 Left-to-right alphabetic scripts
 * 300–399 Alphasyllabic scripts
 * 400–499 Syllabic scripts
 * 500–599 Ideographic scripts
 * 600–699 Undeciphered scripts
 * 700–799 Shorthands and other notations
 * 800–899</tt> (unassigned)
 * 900–999</tt> Private use, alias, special codes

Special codes

 * Qaaa&mdash;Qabx (900&mdash;949)</tt>: 50 Codes reserved for private use.
 * Zinh 994 </tt>: Code for inherited script
 * Zmth 995 </tt>: Mathematical notation
 * Zsym 996 </tt>: Symbols
 * Zxxx 997 </tt>: Code for unwritten languages
 * Zyyy 998 </tt>: Code for undetermined script
 * Zzzz 999 </tt>: Code for uncoded script

Relations to other standards
The following standards are referred to as indispensable by ISO 15924.
 * ISO 639-2:1998 Codes for the representation of names of languages — Part 2: Alpha-3 code
 * ISO/IEC 9541-1:1991 Information technology — Font information interchange — Part 1: Architecture
 * ISO/IEC 10646-1:2000 Information technology — Universal Multiple-Octet Coded Character Set (UCS)

For definition of font and glyph the standard refers to
 * ISO/IEC 9541-1:1991

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