What is 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. Developed in conjunction with the Universal Character Set standard and published in book form as The Unicode Standard, the latest version of Unicode consists of a repertoire of more than 110,000 characters covering 100 scripts, a set of code charts for visual reference, an encoding methodology and set of standard character encodings, an enumeration of character properties such as upper and lower case, a set of reference data computer files, and a number of related items, such as character properties, rules for normalization, decomposition, collation, rendering, and bidirectional display order (for the correct display of text containing both right-to-left scripts, such as Arabic and Hebrew, and left-to-right scripts). As of September 2012, the most recent version is Unicode 6.2.

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Some articles on unicode:

Unicode - Origin and Development - Architecture and Terminology - Character General Category
... Each code point has a single General Category property ... The major categories are Letter, Mark, Number, Punctuation, Symbol, Separator and Other ...
Specials (Unicode Block)
... Specials is the name of a short Unicode block allocated at the very end of the Basic Multilingual Plane, at U+FFF0–FFFF ... Of these 16 codepoints, 5 are assigned as of Unicode 6.0 U+FFF9 interlinear annotation anchor, marks start of annotated text U+FFFA interlinear annotation separator, marks start of ... unassigned in the usual sense, but guaranteed not to be a Unicode character at all ...
Siddhaṃ Alphabet - Unicode
... Siddhaṃ is not yet encoded in the Unicode standard ... the script has been developed by Anshuman Pandey and submitted to the Unicode Technical Committee ...
Celsius - Name and Symbol Typesetting - Unicode Character
... Unicode provides a compatibility character for the degree Celsius at U+2103 (decimal 8451), for compatibility with CJK encodings that provide such a character (as such, in most fonts the width is the same as for ... When viewed on computers that properly support Unicode, the above line may be similar to the image in the line below (enlarged for clarity) The canonical decomposition is simply an ordinary degree sign and "C", so ...
Subscript And Superscript - Position Adjustment in Italic/oblique/slanted Styles - Unicode
... Unicode defines subscript and superscript characters in several areas, in particular it has a full set of superscript and subscript digits ...