Last updated
X x
(See below)
X cursiva.gif
Writing system Latin script
Type Alphabetic and Logographic
Language of origin Latin language
Greek language
Phonetic usage[ x ]
[ χ ]
[ ħ ]
[ ]
[ s ]
[ ʃ ]
[ ɕ ]
[ ]
[ ɗ ]
[ ʔ ]
[ ǁ ]
[ ʃ ]
[ d͡z ]
[ d͡ʒ ]
[ ]
[ z ]
Unicode valueU+0058, U+0078
Alphabetical position24
(speculated origin)
Time period~-700 to present
Descendants  ×
Sisters Х

Variations(See below)
Other letters commonly used with x(x)

X or x is the 24th and third-to-last letter in the modern English alphabet and the ISO basic Latin alphabet. Its name in English is ex (pronounced /ˈɛks/ ), plural exes. [1]



Greek Chi Etruscan
Chi uc lc.svg EtruscanX-01.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/.

Use in writing systems


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). [2] Before 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 (typically used only in British-based spellings of the language; American spellings tend to use -ction). 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); 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-" 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).

X is the third least frequently used letter in English (after q and z), with a frequency of about 0.15% in words. [3]

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 to represent an unknown was introduced by René Descartes in La Géométrie (1637). [5] 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. [6] [7]

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

It may also be 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". [8]

The Roman numeral Ⅹ represents the number 10. [9] [10]

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. [11] 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.

Ancestors and siblings in other alphabets


Computing codes

Unicode 88U+0058120U+0078
UTF-8 885812078
Numeric character reference XXxx
EBCDIC family231E7167A7
ASCII 1885812078
1Also 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.

Operating systems

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

Other representations

NATO phonetic Morse code
ICS X-ray.svg

Semaphore X-ray.svg

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

See also

Related Research Articles

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  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. The Hague: 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 Pronunciation]. Dizionario di ortografia e pronunzia (in Italian). Retrieved 9 February 2014.
  5. Cajori, Florian (1928). A History of Mathematical Notations. Chicago: Open Court Publishing. p. 381. See History of algebra.
  6. Holme, Ingrid (2008). "Hearing People's Own Stories". Science as Culture. 17 (3): 341–344. doi:10.1080/09505430802280784.
  7. "New Zealand Passports - Information about Changing Sex / Gender Identity". Archived from the original on 23 September 2014. Retrieved 6 October 2014.
  8. "X marks the spot" . Retrieved 21 June 2016.
  9. Gordon, Arthur E. (1983). Illustrated Introduction to Latin Epigraphy . University of California Press. p.  44 . Retrieved 3 October 2015. roman numerals.
  10. King, David A. (2001). The Ciphers of the Monks. p. 282. 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.
  11. "X: Mark of Collaboration - Issue No. 0053X - Arkitip, Inc". arkitip.com.
  12. Constable, Peter (2004-04-19). "L2/04-132 Proposal to add additional phonetic characters to the UCS" (PDF).
  13. 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).
  14. Anderson, Deborah; Everson, Michael (2004-06-07). "L2/04-191: Proposal to encode six Indo-Europeanist phonetic characters in the UCS" (PDF).