X

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This article is about the letter of the alphabet. For other uses, see X (disambiguation).
Not to be confused with ×.
Cursive.svg
Circle sheer blue 29.gif
Circle sheer blue 29.gif
Cursive script 'x' and capital 'X'

X (named ex /ˈɛks/, plural exes[1]) is the twenty-fourth letter in the ISO basic Latin alphabet. In Roman numerals, it represents 10.

History[edit]

In Ancient Greek, 'Χ' and 'Ψ' were among several variants of the same letter, used originally for /kʰ/ and later, in western areas such as Arcadia, as a simplification of the digraph 'ΧΣ' for /ks/. In the end, more conservative eastern forms became the standard of Classical Greek, and thus 'Χ' (Chi) stands for /kʰ/ (later /x/). However, the Etruscans had taken over 'Χ' from western Greek, and it therefore stands for /ks/ in Etruscan and Latin.[citation needed]

The letter 'Χ' ~ 'Ψ' for /kʰ/ was a Greek addition to the alphabet, placed after the Semitic letters along with phi 'Φ' for /pʰ/. (The variant 'Ψ' later replaced the digraph 'ΦΣ' for /ps/; omega was a later addition).[citation needed].

Greek ChiEtruscan
 :X
Chi uc lc.svgEtruscanX-01.svg

Use in English[edit]

In English orthography, x is typically pronounced as the voiceless consonant cluster /ks/ when it follows the stressed vowel, and the voiced consonant /ɡz/ when it precedes the stressed vowel (e.g. 'exam'), or when it precedes a silent 'h' and an accented vowel ('exhaust').[2] Before 'i' or 'u' it can also be pronounced /kʃ/ or /ɡʒ/ for example, in the words 'sexual' and 'luxury', respectively: these result from earlier /ksj/ and /ɡzj/. It also makes the sound /kʃ/ in words ending in -xion (typically used only in British-based spellings of the language; American spellings tend to use -ction). Word-final 'x' is always /ks/ (e.g. 'ax'/'axe') except in loan words such as 'faux' (see French, below).

In abbreviations, it can represent "trans-" (e.g. XMIT for transmit, XFER for transfer), "cross-" (e.g. X-ing for crossing; XREF for cross-reference), "Christ" as shorthand for the labarum (e.g. Xmas for Christmas; Xian for Christian), the "Crys" in Crystal (XTAL), or various words starting with "ex" (e.g. XL for extra large; XOR for exclusive-or).

There are very few English words that start with X – the least amount of any letter. Many of the words that do start with X are either standardized trademarks (Xerox) or acronyms (XC). No words in the Basic English vocabulary begin with 'X', but it occurs in words beginning with other letters.

X is the third least common letter in English, with a frequency of about 0.15% in words. It is, however, more frequent than Q and Z.[3]

Use in other languages[edit]

In the International Phonetic Alphabet, [x] represents a voiceless velar fricative.

In Latin, 'x' stood for [ks]. In some languages, as a result of assorted phonetic changes, handwriting adaptations or simply spelling convention, 'x' has other pronunciations:

Additionally, in languages for which the Latin alphabet has been adapted only recently, 'x' has been used for various sounds, in some cases inspired by European usage, but in others, for consonants uncommon in Europe. For these no Latin letter stands out as an obvious choice, and since most of the various European pronunciations of 'x' can be written by other means, the letter becomes available for more unusual sounds.

Usage in Southeast Asia and China[edit]

Metalinguistic usage[edit]

In mathematics, 'x' is commonly used as the name for an independent variable or unknown value. The modern tradition of using 'x' to represent an unknown was started by René Descartes in La Géométrie (1637).[5]

It may also be used to signify the multiplication operation when a more appropriate glyph is unavailable. In mathematical typesetting, 'x' meaning an algebraic variable is normally in italic type (x\!), partly to avoid confusion with the multiplication symbol. In fonts containing both 'x' (the letter) and '×' (the multiplication sign), the two glyphs are dissimilar.

Other non-mathematical uses include:

Computing codes[edit]

CharacterXx
Unicode nameLATIN CAPITAL LETTER X    LATIN SMALL LETTER X
Encodingsdecimalhexdecimalhex
Unicode88U+0058120U+0078
UTF-8885812078
Numeric character referenceXXxx
EBCDIC family231E7167A7
ASCII 1885812078
1 Also for encodings based on ASCII, including the DOS, Windows, ISO-8859 and Macintosh families of encodings.

In the C programming language, 'x' preceded by zero (0x or 0X) is used to denote hexadecimal literal values.

Related letters and other similar characters[edit]

Other representations[edit]

NATO phoneticMorse code
X-ray–··–
ICS X-ray.svgSemaphore X-ray.svg⠭
Signal flagFlag semaphoreBraille
dots-1346

See also[edit]

References[edit]

  1. ^ "X", Oxford English Dictionary, 2nd edition (1989); Merriam-Webster's Third New International Dictionary of the English Language, Unabridged (1993); "ex", op. cit.
  2. ^ Venezky, Richard (1 January 1970). The Structure of English Orthography. Walter de Gruyter. p. 40. ISBN 978-3-11-080447-8. 
  3. ^ Mička, Pavel. "Letter frequency (English)". Algoritmy.net. Retrieved 9 February 2014. 
  4. ^ "Dizionario di ortografia e pronunzia" [Dictionary of Spelling and preliminary]. Dizionario di ortografia e pronunzia (in Italian). Retrieved 9 February 2014. 
  5. ^ Cajori, Florian (1993). "A History of Mathematical Notations". Google Books (Dover Publications). 

External links[edit]