X

X
	X x
	(See below)
Usage
Writing system	Latin script
Type	Alphabetic and Logographic
Language of origin	Latin language ; Greek language
Phonetic usage	[ x ]; [ χ ]; [ ħ ]; [ kʰ ]; [ k͡ s ]; [ ʃ ]; [ ɕ ]; [ tʼ ]; [ ɗ ]; [ ʔ ]; [ ǁ ]; [ k͡ ʃ ]; [ d͡z ]; [ d͡ʒ ]; [ sʲ ]; [ z ]; [Ø]; /ɛks/
Unicode value	U+0058, U+0078
Alphabetical position	24
History
Time period	~-700 to present
Descendants	• × ; • ℵ ; • ⨘ ; • ⨉ ; • ⨯ ; • ✗ ; • ☒ ; • ꭓ ; • X̧
Sisters	Х ; 𐍇 ; Ⴕ ქ ; Ⴟ ჯ
Variations	(See below)
Other
Other letters commonly used with	x(x)
	This article contains IPA phonetic symbols. Without proper rendering support, you may see question marks, boxes, or other symbols instead of Unicode characters. For an introductory guide on IPA symbols, see Help:IPA.

Last updated May 05, 2019

X (named ex /ɛks/ , plural exes^[1]) is the 24th and antepenultimate letter in the modern English alphabet and the ISO basic Latin alphabet.

A letter is a grapheme in an alphabetic system of writing. It is a visual representation of the smallest unit of spoken sound. Letters broadly correspond to phonemes in the spoken form of the language, although there is rarely a consistent, exact correspondence between letters and phonemes.

English alphabet Latin alphabet consisting of 26 letters, each having an uppercase and a lowercase form

The modern English alphabet is a Latin alphabet consisting of 26 letters, each having an upper- and lower-case form. The same letters constitute the ISO basic Latin alphabet. The alphabet's current form originated in about the 7th century from the Latin script. Since then, various letters have been added, or removed, to give the current Modern English alphabet of 26 letters:

The ISO basic Latin alphabet is a Latin-script alphabet and consists of two sets of 26 letters, codified in various national and international standards and used widely in international communication. They are the same letters that comprise the English alphabet.

History

Greek Chi	Etruscan :X

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 Ancient Greek language includes the forms of Greek used in Ancient Greece and the ancient world from around the 9th century BCE to the 6th century CE. It is often roughly divided into the Archaic period, Classical period, and Hellenistic period. It is antedated in the second millennium BCE by Mycenaean Greek and succeeded by medieval Greek.

Arcadia is one of the regional units of Greece. It is part of the administrative region of Peloponnese. It is situated in the central and eastern part of the Peloponnese peninsula. It takes its name from the mythological figure Arcas. In Greek mythology, it was the home of the god Pan. In European Renaissance arts, Arcadia was celebrated as an unspoiled, harmonious wilderness.

Digraph (orthography) pair of characters used to write one phoneme

A digraph or digram is a pair of characters used in the orthography of a language to write either a single phoneme, or a sequence of phonemes that does not correspond to the normal values of the two characters combined.

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

English

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).

English orthography is the system of writing conventions used to represent spoken English in written form that allows readers to connect spelling to sound to meaning.

In linguistics, a consonant cluster, consonant sequence or consonant compound is a group of consonants which have no intervening vowel. In English, for example, the groups and are consonant clusters in the word splits.

There are very few English words that start with ⟨x⟩ (the fewest number 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).

Xiaomi Corporation is a Chinese electronics company headquartered in Beijing. Xiaomi makes and invests in smartphones, mobile apps, laptops, and related consumer electronics.

Xinjiang, officially the Xinjiang Uygur Autonomous Region (XUAR), is a provincial-level autonomous region of China in the northwest of the country. It is the largest Chinese administrative division and the eighth largest country subdivision in the world, spanning over 1.6 million km². Xinjiang contains the disputed territory of Aksai Chin, which is administered by China and claimed by India. Xinjiang borders the countries of Mongolia, Russia, Kazakhstan, Kyrgyzstan, Tajikistan, Afghanistan, Pakistan (Gilgit-Baltistan), and India. The rugged Karakoram, Kunlun, and Tian Shan mountain ranges occupy much of Xinjiang's borders, as well as its western and southern regions. Xinjiang also borders Tibet Autonomous Region and the provinces of Gansu and Qinghai. The most well-known route of the historical Silk Road ran through the territory from the east to its northwestern border. In recent decades, abundant oil and mineral reserves have been found in Xinjiang, and it is currently China's largest natural gas-producing region.

Greek is an independent branch of the Indo-European family of languages, native to Greece, Cyprus and other parts of the Eastern Mediterranean and the Black Sea. It has the longest documented history of any living Indo-European language, spanning more than 3000 years of written records. Its writing system has been the Greek alphabet for the major part of its history; other systems, such as Linear B and the Cypriot syllabary, were used previously. The alphabet arose from the Phoenician script and was in turn the basis of the Latin, Cyrillic, Armenian, Coptic, Gothic, and many other writing systems.

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

The frequency of letters in text has been studied for use in cryptanalysis, and frequency analysis in particular, dating back to the Iraqi mathematician Al-Kindi, who formally developed the method.

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:

In Basque, ⟨x⟩ represents [ʃ]. Additionally there is the digraph ⟨tx⟩[tʃ].
In Dutch, ⟨x⟩ usually represents [ks], except in the name of the island of Texel, which is pronounced Tessel. This is because of historical sound-changes in Dutch, where all /ks/ sounds have been replaced by /s/ sounds. Words with an ⟨x⟩ in the Dutch language are nowadays usually loanwords. In the Dutch-speaking part of Belgium, family names with ⟨x⟩ are not uncommon (e.g. Dierckx, Hendrickx, Koninckx, Sterckx, Vranckx).
In Norwegian, ⟨x⟩ is generally pronounced [ks], but since the 19th century, there has been a tendency to spell it out as ⟨ks⟩; it may still be retained in personal names, though it is fairly rare, and occurs mostly in foreign words and SMS language. Usage in Danish and Finnish is similar (while Swedish, on the other hand, makes frequent use of ⟨x⟩ in native words as well as in loanwords).
In German, generally pronounced [ks]; in native words, however,such as Ochs or wachsen, the cluster [ks] is often written ⟨chs⟩.
French : at the ends of words, silent (or [z] in liaison if the next word starts with a vowel). Three exceptions are pronounced [s]: six ("six"), dix ("ten") and in some city names such as Bruxelles (although some people pronounce it 'ks') or Auxerre ; it is fully pronounced [ks] in Aix, Aix-les-Bains, Aix-la-Chapelle . It is pronounced [z] in sixième and dixième. Otherwise [ks] or (primarily in words beginning with ex- followed by a vowel) [ɡz].
In Italian, ⟨x⟩ is either pronounced [ks], as in extra, uxorio, xilofono,^[4] or [ɡz], as exogamia, when it is preceded by ⟨e⟩ and followed by a vowel. In several related languages, notably Venetian, it represents the voiced sibilant [z]. It is also used, mainly amongst the young people, as a short written form for "per", meaning "for": for example, "x sempre" ("forever"). This is because in Italian the multiplication sign (similar to ⟨x⟩) is called "per". However, ⟨x⟩ is found only in loanwords, as it is not part of the standard Italian alphabet; in most words with ⟨x⟩, this letter may be replaced with 's' or 'ss' (with different pronunciation: xilofono/silofono, taxi/tassì) or, rarely, by 'cs' (with the same pronunciation: claxon/clacson ).
In Old Spanish, ⟨x⟩ was pronounced [ʃ], as it is still currently in other Iberian Romance languages. Later, the sound evolved to a hard [x] sound. In modern Spanish, due to a spelling reform, whenever ⟨x⟩ is used for the [x] sound it has been replaced with ⟨j⟩, including in words that originally had ⟨x⟩ such as ejemplo or ejercicio, though ⟨x⟩ is still retained for some names (notably 'México', even though 'Méjico' may sometimes be used in Spain). Presently, ⟨x⟩ represents the sound [s] (word-initially), or the consonant cluster [ks] (e.g. oxígeno, examen). Rarely, it can be pronounced [ʃ] as in Old Spanish in some proper nouns such as 'Raxel' (a variant of Rachel) and Uxmal .
In Galician and Leonese, ⟨x⟩ is pronounced [ʃ] in most cases. In learned words, such as 'taxativo' (taxing), it is pronounced [ks]. However, Galician speakers tend to pronounce it [s], especially when it appears before plosives, such as in 'externo' (external).
In Catalan, ⟨x⟩ has three sounds; the most common is [ʃ]; as in 'xarop' (syrup). Other sounds are: [ks]; 'fixar' (to fix), [ɡz]; 'examen'. In addition, [ʃ] gets voiced to [ʒ] before voiced consonants; 'caixmir'. Catalan also has the digraph ⟨tx⟩, pronounced [tʃ].
In Portuguese, ⟨x⟩ has four main sounds; the most common is [ʃ], as in 'xícara' (cup). The other sounds are: [ks] as in 'flexão' (flexion); [s], when preceded by E and followed by a consonant, as in 'contexto' ([ʃ] in European Portuguese), and in a small number of other words, such as 'próximo' (close/next); and (the rarest) [z], which occurs in the prefix 'ex-' before a vowel, as in 'exagerado' (exaggerated). A rare fifth sound is [ɡz], coexisting with [z] and [ks] as acceptable pronunciations in exantema and in words with the Greek prefix 'hexa-'.
In Venetian, it represents the voiced alveolar sibilant [z] much like in Portuguese 'exagerado', English 'xylophone' or in the French 'sixième'. Examples from medieval texts include raxon (reason), prexon (prison), dexerto (desert), chaxa/caxa (home). Nowadays, the best-known word is xe (is/are). The most notable exception to this rule is the name Venexia[veˈnɛsja] in which ⟨x⟩ has evolved from the initial voiced sibilant [z] to the present day voiceless sibilant.
In Albanian, ⟨x⟩ represents [dz], while the digraph ⟨xh⟩ represents [dʒ].
In Maltese, ⟨x⟩ is pronounced [ʃ] or, in some cases, [ʒ] (only in loanwords such as 'televixin', and not for all speakers).
In Polish, ⟨x⟩ was used prior to 19th century both in loanwords and native words and was pronounced [ks] or [ɡz], e.g. xiążę, xięstwo (now książę, księstwo). Later was replaced by ⟨ks⟩ and ⟨gz⟩ in all words and remained only in surnames as Axentowicz, Jaxa, Koxowski, Mixtacki, Rexemowski, Xiężopolski, names as Xawery, Xymena and abbreviations.

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.

⟨x⟩ represents [x] (voiceless velar fricative) in e.g. Azerbaijani, Kurdish, Lojban, Tatar, Uzbek, Pashto and Uyghur (Latin script).
Esperanto: The x-convention replaces ⟨ ĉ ⟩, ⟨ ĝ ⟩, ⟨ ĥ ⟩, ⟨ ĵ ⟩, ⟨ ŝ ⟩, and ⟨ ŭ ⟩ with x-suffixes: ⟨cx⟩, ⟨gx⟩, ⟨hx⟩, ⟨jx⟩, ⟨sx⟩, and ⟨ux⟩.
In transliteration of Indian languages, ⟨x⟩ represents the consonant cluster [kʃ] in alternate spellings of words containing 'क्ष' (kṣ), especially names such as Laxmi and Dixit. Less frequently, ⟨x⟩ is used to represent 'ख़' [x].
In Apache ⟨x⟩ represents [x]
In Nahuatl, ⟨x⟩ represents [ʃ].
In Nguni languages, ⟨x⟩ represents the alveolar lateral click [ǁ].
In Pirahã, ⟨x⟩ symbolizes the glottal stop [ʔ].
An illustrating example of "x" as a "leftover" letter is differing usage in three different Cushitic languages:
- Afar: voiced alveolar implosive [ɗ]
- Oromo: alveolar ejective [tʼ]
- Somali: voiceless pharyngeal fricative [ħ]
In Asia:
- In Lao, based on romanization of Lao consonants, ⟨x⟩ may represent [ɕ], e.g. in Lan Xang.
- In Vietnamese, ⟨x⟩ is pronounced like English ⟨s⟩ (at the beginning of a word, e.g. "sing"). This sound was [ɕ] in Middle Vietnamese, resembling the Portuguese sound /ʃ/, spelled ⟨x⟩.
- In Hanyu Pinyin, Standard Chinese's official transcription system in China, Malaysia, Singapore, and Taiwan, the letter ⟨x⟩ represents the voiceless alveolo-palatal fricative /ɕ/, for instance in 'Xi', [ɕi].

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).

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 ( $x\!$ ), partly to avoid confusion with the multiplication symbol. In fonts containing both x (the letter) and × (the multiplication sign), the two glyphs are dissimilar.

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".^[6]

The Roman numeral Ⅹ represents the number 10.^[7]^[8]

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.^[9] This usage mimics the use of a similar mark in denoting botanical hybrids, for which scientifically the multiplication sign (×) is used, but informally a lowercase "x" is also used.

Related characters

Descendants and related characters in the Latin alphabet

X with diacritics: Ẍ ẍ Ẋ ẋ ᶍ ^[10]
IPA-specific symbols related to X: χ
Teuthonista phonetic transcription-specific symbols related to X:^[11]
- U+AB56ꭖLATIN SMALL LETTER X WITH LOW RIGHT RING
- U+AB57ꭗLATIN SMALL LETTER X WITH LONG LEFT LEG
- U+AB58ꭘLATIN SMALL LETTER X WITH LONG LEFT LEG AND LOW RIGHT RING
- U+AB59ꭙLATIN SMALL LETTER X WITH LONG LEFT LEG WITH SERIF
ˣ : Modifier letter small x is used for phonetic transcription
ₓ : Subscript small x is used in Indo-European studies ^[12]

Ancestors and siblings in other alphabets

Χ χ : Greek letter Chi, from which the following derive:
- Х х : Cyrillic letter Kha
- Ⲭ ⲭ : Coptic letter Khe, which derives from Greek Chi
- 𐍇 : Gothic letter enguz, which derives from Greek Chi
- 𐌗 : Old Italic X, which derives from Greek Chi, and is the ancestor of modern Latin X
  - ᚷ : Runic letter Gyfu, which may derive from old Italic X
Ξ ξ : Greek letter Xi, which was used in place of Chi in the Eastern (and the modern) Greek alphabets

Computing codes

Character	X		x
Unicode name	LATIN CAPITAL LETTER X		LATIN SMALL LETTER X
Encodings	decimal	hex	decimal	hex
Unicode	88	U+0058	120	U+0078
UTF-8	88	58	120	78
Numeric character reference	X	X	x	x
EBCDIC family	231	E7	167	A7
ASCII ¹	88	58	120	78

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 (0x or 0X) is used to denote hexadecimal literal values.

Other representations

NATO phonetic	Morse code
X-ray	–··–


Signal flag	Flag semaphore	American manual alphabet (ASL fingerspelling)	Braille dots-1346

References

↑ "X", Oxford English Dictionary , 2nd edition (1989); Merriam-Webster's Third New International Dictionary of the English Language, Unabridged (1993); "ex", op. cit.
↑ Venezky, Richard (1 January 1970). The Structure of English Orthography. The Hague: Walter de Gruyter. p. 40. ISBN 978-3-11-080447-8.
↑ Mička, Pavel. "Letter frequency (English)". Algoritmy.net. Retrieved 9 February 2014.
↑ "Dizionario di ortografia e pronunzia" [Dictionary of Spelling and Pronunciation]. Dizionario di ortografia e pronunzia (in Italian). Retrieved 9 February 2014.
↑ Cajori, Florian (1928). A History of Mathematical Notations. Chicago: Open Court Publishing. p. 381. See History of algebra.
↑ "X marks the spot" . Retrieved 21 June 2016.
↑ Gordon, Arthur E. (1983). Illustrated Introduction to Latin Epigraphy. University of California Press. p. 44. Retrieved 3 October 2015.
↑ 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.
↑ "X: Mark of Collaboration - Issue No. 0053X - Arkitip, Inc". arkitip.com.
↑ Constable, Peter (2004-04-19). "L2/04-132 Proposal to add additional phonetic characters to the UCS" (PDF).
↑ 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).
↑ Anderson, Deborah; Everson, Michael (2004-06-07). "L2/04-191: Proposal to encode six Indo-Europeanist phonetic characters in the UCS" (PDF).

External links

Media related to X at Wikimedia Commons
The dictionary definition of X at Wiktionary
The dictionary definition of x at Wiktionary
"X" . The American Cyclopædia . 1879.

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Text is available under the CC BY-SA 4.0 license; additional terms may apply.
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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.

[Venezky1970-2] 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] "X marks the spot" . Retrieved 21 June 2016.

[7] Gordon, Arthur E. (1983). Illustrated Introduction to Latin Epigraphy. University of California Press. p. 44. Retrieved 3 October 2015.

[8] 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.

[9] "X: Mark of Collaboration - Issue No. 0053X - Arkitip, Inc". arkitip.com.

[10] Constable, Peter (2004-04-19). "L2/04-132 Proposal to add additional phonetic characters to the UCS" (PDF).

[11] 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).

[12] Anderson, Deborah; Everson, Michael (2004-06-07). "L2/04-191: Proposal to encode six Indo-Europeanist phonetic characters in the UCS" (PDF).

X

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