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X x
Writing systemLatin script
TypeAlphabetic and Logographic
Language of originLatin language
Greek language
Phonetic usage[x]
Unicode codepointU+0058, U+0078
Alphabetical position24
(speculated origin)
Time period~-700 to present
Descendants • ×
 • ⨘

Other letters commonly used withx(x)
This article contains phonetic transcriptions in the International Phonetic Alphabet (IPA). For an introductory guide on IPA symbols, see Help:IPA. For the distinction between [ ], / / and  , see IPA § Brackets and transcription delimiters.

X, or x, is the twenty-fourth and third-to-last letter in the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is "ex" (pronounced /ˈɛks/), plural exes.[2] X is regularly pronounced as "ks".


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Greek Chi Etruscan
Chi uc lc.svg

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) stood for /kʰ/ (later /x/; palatalized to [ç] in Modern Greek before front vowels). However, the Etruscans had taken over 'Χ' from western Greek, and it therefore stands for /ks/ in Etruscan and Latin.

The letter 'Χ' ~ 'Ψ' for /kʰ/ was a Greek addition to the alphabet, placed after the Semitic letters along with phi 'Φ' for /pʰ/.

Pronunciation and use

Pronunciations of Xx
Language Dialect(s) Pronunciation (IPA) Environment Notes
Afar /ɖ/
Albanian /dz/ xh=//
Azeri /x/
Basque /ʃ/ tx=//
Catalan /gz/
/ʃ/ Usually (word-initially, after consonants, i, au, eu, in some surnames such as Rexach)
Mandarin Chinese Standard Mandarin /ɕ/ In Pinyin latinization
Cou /ɨ/ ~ /ʉ/ Possibly the only case in the world of <x> used as a vowel.
Dutch /ks/ Usually Letter mainly used in loanwords
/s/ In Texel
English /gz/ Before a stressed vowel
/gʒ/ Only in luxury and derivatives
/h/ Don Quixote, Oaxaca, words derived from Classical Nahuatl/Nahuatl
/ks/ Usually; before an unstressed vowel
/kʃ/ Groups -xion(-), -xious(-), -xua-; in the word flexure
/z/ Word-initially
Esperanto in digraphs only cx, gx, hx, jx, sx, ux are used as substitutes for ĉ, ĝ, ĥ, ĵ, ŝ, ŭ where these characters are not available. See X-convention
French /gz/ Mainly in the prefix ex- followed by a vowel; sometimes word-initially
/ks/ Usually; in Aix- (prefix or name of several places)
/s/ In six (6), dix (10), Auxerre, and Bruxelles (Brussels)
silent Word-finally with no liaison
/z/ Word-finally with liaison; in sixième (6th) and dixième (10th)
Galician /(k)s/ Some words In learned loanwords
/ʃ/ Usually
German /ks/ Letter mainly used in loanwords
Indonesian /s/ In the beginning of a word Mainly used in loanwords for science
/ks/ In the middle or the end of a word, although words borrowed with the letter x in the middle or the end of a word are always replaced by the letters 'ks'. For example, the word 'maximum' and 'climax' in Indonesian would be 'maksimal' and 'klimaks'. Letter x on the middle or the end of a word only occurs in names.
Italian /ks/ Letter mainly used in learned loanwords
Kurdish /x/
Lao /ɕ/ Latinization
Leonese /ʃ/
Ligurian /ʒ/
Maltese /ʃ/
Mayan /ʃ/ Modern Romanization
Nahuatl /ʃ/
Nguni /ǁ/
Norwegian /ks/ Archaic
Occitan /t͡s/ Usually
/s/ Before consonants
/ɡz/ In the prefix ex- before vowels In the Provençal, Limousin, Auvergnat, Vivaro-Alpine, and Niçard dialects
/ɡʒ/ Before the vowels “i” & “u” In the Auvergnat dialect
Oromo //
Pirahã /ʔ/
Polish /ks~gz/
Portuguese /gz/ In the prefix hexa- ("hexa-")
/ks/ Some words Mainly in learned loanwords
/s/ When preceded by <e> and a consonant; some words
/ʃ/ Word-initially; in words derived from Tupi; usually
/z/ In the prefix ex- ("ex-") before a vowel
Sardinian /ʒ/
Sicilian /ʃ/ Pronunciation for Old Sicilian words See e.g. Craxi, Joppolo Giancaxio
/k(ə)s(ə)/ Pronunciations for loanwords
Somali /ħ/, /ʜ/
Spanish /(k)s/ Usually
/s/ Word-initially
/ʃ/ In some names and words
Swedish /ks/
Uzbek /χ/
Venetian /s/ In Venexia "Venice"
/z/ Usually
Vietnamese /s/


In English orthography, ⟨x⟩ is typically pronounced as the voiceless consonant cluster /ks/ when it follows the stressed vowel (e.g. ox), and the voiced consonant /ɡz/ when it precedes the stressed vowel (e.g. exam). It is also pronounced /ɡz/ when it precedes a silent ⟨h⟩ and a stressed vowel (e.g. exhaust).[3] Before ⟨a⟩, ⟨i⟩ or ⟨u⟩, it can be pronounced /kʃ/ or /ɡʒ/ (e.g. sexual and luxury); these result from earlier /ksj/ and /ɡzj/. It also makes the sound /kʃ/ in words ending in -xion (except for axion). When ⟨x⟩ ends a word, it is always /ks/ (e.g. fax), except in loan words such as faux (see French, below).

There are very few English words that start with ⟨x⟩ (the fewest of any letter). When ⟨x⟩ does start a word, it is usually pronounced 'z' (e.g. xylophone, xenophobia, and xanthan). When starting in some names or as its own representation it is pronounced 'eks', in rare recent loanwords or foreign proper names, it can also be pronounced /s/ (e.g. the obsolete Vietnamese monetary unit xu) or /ʃ/ (e.g. Chinese names starting with Xi like Xiaomi or Xinjiang). Many of the words that start with ⟨x⟩ are of Greek origin, or standardized trademarks (Xerox) or acronyms (XC). 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-" (e.g. Xmas for Christmas, Xian for Christian), the "crys-" in crystal (XTAL), "by" (SXSW for South by Southwest) or various words starting with "ex-" (e.g. XL for extra large, XOR for exclusive-or, or the extinction symbol).

X is the third least frequently used letter in English (after ⟨q⟩ and ⟨z⟩), with a frequency of about 0.15% in words.[4]

Other languages

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.

Other systems

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

Other uses

In mathematics, x is commonly used as the name for an independent variable or unknown value. The modern tradition of using x, y and z to represent an unknown (incognita) was introduced by René Descartes in La Géométrie (1637).[6] As a result of its use in algebra, X is often used to represent unknowns in other circumstances (e.g. X-rays, Generation X, The X-Files, and The Man from Planet X; see also Malcolm X).

On some identification documents, the letter X represents a non-binary gender, where F means female and M means male.[7][8]

In the Cartesian coordinate system, x is used to refer to the horizontal axis.

It is also sometimes used as a typographic approximation for the multiplication sign, ×. In mathematical typesetting, x meaning an algebraic variable is normally in italic type (), partly to avoid confusion with the multiplication symbol. In fonts containing both x (the letter) and × (the multiplication sign), the two glyphs are dissimilar.

It can be used as an abbreviation for 'between' in the context of historical dating; e.g., '1483 x 1485'.

Maps and other images sometimes use an X to label a specific location, leading to the expression "X marks the spot".[9]

The Roman numeral X represents the number 10.[10][11]

The Suzhou numeral 〤 represents the number 4.

In art or fashion, the use of X indicates a collaboration by two or more artists, e.g. Aaron Koblin x Takashi Kawashima. This application, which originated in Japan, now extends to other kinds of collaboration outside the art world.[12] This usage mimics the use of a similar mark in denoting botanical hybrids, for which scientifically the multiplication × is used, but informally a lowercase "x" is also used.

At the end of a letter or other correspondence, 'x' can mean a kiss;[13] the earliest example of this usage cited by the Oxford English Dictionary is from 1878.[14]

An X rating denotes media such as movies that are intended for adults only.

Related characters

Descendants and related characters in the Latin alphabet

Ancestors and siblings in other alphabets


Computing codes

Character information
Preview X x
Encodings decimal hex dec hex
Unicode 88 U+0058 120 U+0078
UTF-8 88 58 120 78
Numeric character reference &#88; &#x58; &#120; &#x78;
EBCDIC family 231 E7 167 A7
ASCII 1 88 58 120 78
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 (as in 0x or 0X) is used to denote hexadecimal literal values.

X is commonly used as a prefix term in nouns related to the X Window System and Unix.[2]

Other representations

NATO phonetic Morse code
  ▄▄▄ ▄ ▄ ▄▄▄ 
ICS X-ray.svg

Semaphore X-ray.svg

Sign language X.svg
BSL letter X.svg
Signal flag Flag semaphore American manual alphabet (ASL fingerspelling) British manual alphabet (BSL fingerspelling) Braille dots-1346
Unified English Braille

See also


  1. ^ as in the English word luxurious
  2. ^ a b "X", Oxford English Dictionary, 2nd edition (1989); Merriam-Webster's Third New International Dictionary of the English Language, Unabridged (1993); "ex", op. cit.
  3. ^ Venezky, Richard (1 January 1970). The Structure of English Orthography. The Hague: Walter de Gruyter. p. 40. ISBN 978-3-11-080447-8. Archived from the original on 27 April 2017. Retrieved 29 October 2016.
  4. ^ Mička, Pavel. "Letter frequency (English)". Archived from the original on 4 March 2021. Retrieved 9 February 2014.
  5. ^ "Dizionario di ortografia e pronunzia" [Dictionary of Spelling and Pronunciation]. Dizionario di ortografia e pronunzia (in Italian). Archived from the original on 16 April 2018. Retrieved 9 February 2014.
  6. ^ Cajori, Florian (1928). A History of Mathematical Notations. Chicago: Open Court Publishing. p. 381. ISBN 9780486161167. Archived from the original on 2021-04-13. Retrieved 2020-11-22. See History of algebra.
  7. ^ Holme, Ingrid (2008). "Hearing People's Own Stories". Science as Culture. 17 (3): 341–344. doi:10.1080/09505430802280784. S2CID 143528047.
  8. ^ "New Zealand Passports - Information about Changing Sex / Gender Identity". Archived from the original on 23 September 2014. Retrieved 6 October 2014.
  9. ^ "X marks the spot". Archived from the original on 4 June 2016. Retrieved 21 June 2016.
  10. ^ Gordon, Arthur E. (1983). Illustrated Introduction to Latin Epigraphy. University of California Press. p. 44. ISBN 9780520038981. Retrieved 3 October 2015. roman numerals.
  11. ^ King, David A. (2001). The Ciphers of the Monks. p. 282. ISBN 9783515076401. Archived from the original on 2021-01-04. Retrieved 2020-11-22. In the course of time, I, V and X became identical with three letters of the alphabet; originally, however, they bore no relation to these letters.
  12. ^ "X: Mark of Collaboration - Issue No. 0053X - Arkitip, Inc". Archived from the original on 2016-05-17. Retrieved 2016-03-22.
  13. ^ Epstein, Nadine (2020-10-07). "A whole lot of history behind 'x' and 'o', kiss and hug". The Washington Post. Archived from the original on 2018-04-01. Retrieved 2021-03-12.
  14. ^ "X, n." OED Online (Oxford: Oxford University Press, September 2022), §6. Accessed 11 November 2022.
  15. ^ Constable, Peter (2004-04-19). "L2/04-132 Proposal to add additional phonetic characters to the UCS" (PDF). Archived (PDF) from the original on 2017-10-11. Retrieved 2018-03-24.
  16. ^ Everson, Michael; Dicklberger, Alois; Pentzlin, Karl; Wandl-Vogt, Eveline (2011-06-02). "L2/11-202: Revised proposal to encode "Teuthonista" phonetic characters in the UCS" (PDF). Archived (PDF) from the original on 2017-10-11. Retrieved 2018-03-24.
  17. ^ Anderson, Deborah; Everson, Michael (2004-06-07). "L2/04-191: Proposal to encode six Indo-Europeanist phonetic characters in the UCS" (PDF). Archived (PDF) from the original on 2017-10-11. Retrieved 2018-03-24.