| Abjad | A writing system in which only consonants are indicated. The term “abjad” is derived from the first four letters of the traditional order of the Arabic script- alef, beh, jeem, dal. (See Section 6.1, Writing Systems.) |
| Abstract Character | A unit of information used for the organization, control, or representation of textual data. (See definition D7 in Section 3.4, Characters and Encoding.) |
| Abstract Character Sequence | An ordered sequence of one or more abstract characters. (See definition D8 in Section Section 3.4, Characters and Encoding.) |
| Abugida | A writing system in which consonants are indicated by the base letters that have an inherent vowel, and in which other vowels are indicated by additional distinguishing marks of some kind modifying the base letter. The term “abugida” is derived from the first four letters of the Ethiopic script in the Semitic order- alf, bet, gaml, dant. (See Section 6.1, Writing Systems.) |
| Accent Mark | A mark placed above, below, or to the side of a character to alter its phonetic value. (See also diacritic.) |
| Acrophonic | Denoting letters or numbers by the first letter of their name. For example, the Greek acrophonic numerals are variant forms of such initial letters. |
| Aksara | (1) In Sanskrit grammar, the term for “letter” in general, as opposed to consonant (vyanjana) or vowel (svara). Derived from the first and last letters of the traditional ordering of Sanskrit letters—“a” and “ksha”. (2) More generally, in Indic writing systems, aksara refers to a “syllable,” consisting of a consonant plus vowel sequence, where the vowel may or may not be the inherent vowel of the consonant letter. When multiple consonants are involved, the aksara represents the entire orthographic syllable, which can include two or more leading consonants that may be visually presented in conjunct forms; in such cases, the aksara may not be identical to the phonological syllable. |
| Algorithm | A term used in a broad sense in the Unicode Standard, to mean the logical description of a process used to achieve a specified result. This does not require the actual procedure described in the algorithm to be followed; any implementation is conformant as long as the results are the same. |
| Alphabet | A writing system in which both consonants and vowels are indicated. The term “alphabet” is derived from the first two letters of the Greek script- alpha, beta. (See Section 6.1, Writing Systems.) |
| Alphabetic Property | Informative property of the primary units of alphabets and/or syllabaries. (See Section 4.10, Letters, Alphabetic, and Ideographic.) |
| Alphabetic Sorting | (See collation.) |
| Annotation | The association of secondary textual content with a point or range of the primary text. (The value of a particular annotation is considered to be a part of the “content” of the text. Typical examples include glossing, citations, exemplification, Japanese yomi, and so on.) |
| ANSI | (1) The American National Standards Institute. (2) The Microsoft collective name for all Windows code pages. Sometimes used specifically for code page 1252, which is a superset of ISO/IEC 8859-1. |
| Apparatus Criticus | Collection of conventions used by editors to annotate and comment on text. |
| Arabic Digits | Forms of decimal digits used in most parts of the Arabic world (for instance, U/0660, U/0661, U/0662, U/0663). Although European digits (1, 2, 3,…) derive historically from these forms, they are visually distinct and are coded separately. (Arabic digits are sometimes called Indic numerals; however, this nomenclature leads to confusion with the digits currently used with the scripts of India.) Arabic digits are referred to as Arabic-Indic digits in the Unicode Standard. Variant forms of Arabic digits used chiefly in Iran and Pakistan are referred to as Eastern Arabic-Indic digits. (See Section 8.2, Arabic.) |
