View source for X

{{Short description|24th letter of the Latin alphabet}}
{{Hatnote group|
{{Technical reasons|:X|the keyboard symbol|List of emoticons}}
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{{Use dmy dates|date=July 2024}}{{About|the letter|other uses}}
{{More citations needed|date=July 2022}}
{{Infobox grapheme
|name=X
|letter=X x
|script=[[Latin script]]
|type=[[Alphabet]]
|typedesc=ic and [[logographic]]
|language=[[Latin language]]<br>[[Greek language]]
|phonemes={{grid list|[{{IPAlink|x}}]|[{{IPAlink|χ}}]|[{{IPAlink|ħ}}]|[{{IPAlink|kʰ}}]|[{{IPAlink|k}}{{IPAlink|s}}]|[{{IPAlink|ʃ}}]|[{{IPAlink|ɕ}}]|[{{IPAlink|tʼ}}]|[{{IPAlink|ʒ}}]|[{{IPAlink|ɖ}}]|[{{IPAlink|ʔ}}]|[{{IPAlink|ǁ}}]|[{{IPAlink|ɡ}}{{IPAlink|ʒ}}]<ref>as in the [[English Language|English]] word [[wikt:luxurious|''lu'''xu'''rious'']]</ref>|[{{IPAlink|k|k}}{{IPAlink|ʃ}}]|[{{IPAlink|d͡z}}]|[{{IPAlink|d͡ʒ}}]|[{{IPAlink|t͡s}}]|[{{IPAlink|t͡ʃ}}]|[{{IPAlink|sʲ}}]|[{{IPAlink|z}}]|[{{IPAlink|ɡ}}{{IPAlink|z}}]|{{IPAblink|∅}}|{{IPAc-en|ɛ|k|s}}}}
|unicode=U+0058, U+0078
|alphanumber=24
|number=
|fam1=[[wikt:𓊽|𓊽]]
|fam2=[[wikt:𐤎|𐤎]]
|usageperiod=~−700 to present
|children={{grid list|[[×]]|[[⨘]]|[[⨉]]|[[⨯]]|[[✗]]|[[☒]]|[[ꭓ]]|[[X̧]]}}
|sisters={{grid list|[[Х]]|[[𐍇]]|[[Ⴕ]] [[ქ]]|[[Ⴟ]] [[ჯ]]}}
|equivalents= 
|associates=[[List of Latin-script digraphs#X|x(x)]]
|direction=Left-to-right
|fam3=[[wikt:𐤎|𐤎]]|fam4=[[Xi (letter)|𐊑]]|fam5=[[Chi (letter)|𐊐]]|fam6=[[𐌗|𐊐]]
|image=File:Latin_letter_X.svg
|imageclass=skin-invert-image
}}
{{Latin letter info|x}}

'''X''', or '''x''', is the twenty-fourth [[Letter (alphabet)|letter]] of the [[Latin alphabet]], used in the [[English alphabet|modern English alphabet]], the alphabets of other western European languages and others worldwide. Its name in English is [[Wikt:ex#English|''ex'']] (pronounced {{IPAc-en|'|ɛ|k|s}}), plural ''exes''.<ref name=":1">"X", ''[[Oxford English Dictionary]]'', 2nd edition (1989); ''Merriam-Webster's Third New International Dictionary of the English Language, Unabridged'' (1993); "ex", ''op. cit''.</ref>

==History==
{{Unreferenced|section|date=February 2025}}
{| class="wikitable"
|-
! Western Greek<br />[[Chi (letter)|Chi]]
! Etruscan<br />X
! Latin<br />X
|- style="background-color:white; text-align:center;"
| [[Image:Greek Chi normal.svg|45px]]
| [[Image:EtruscanX-01.svg|25px]]
| [[File:Capitalis monumentalis X.SVG|x30px]]
|}

The letter {{angbr|X}}, representing {{IPA|/ks/}}, was inherited from the [[Etruscan alphabet]]. It perhaps originated in the {{angbr|Χ}} of the [[Archaic Greek alphabets#Euboean|Euboean alphabet]] or another Western Greek alphabet, which also represented {{IPA|/ks/}}. Its relationship with the {{angbr|Χ}} of the Eastern Greek alphabets, which represented {{IPA|/kʰ/}}, is uncertain.

The pronunciation of {{IPA|/ks/}} in the [[Romance languages]] underwent [[Palatalization in the Romance languages|sound changes]], with various outcomes:
* [[French language|French]]: {{IPA|/js/}} (e.g. ''laisser'' from ''laxare'')
* [[Italian language|Italian]]: {{IPA|/ss/}} (e.g. ''asse'' from ''axem'') and, in some cases, {{IPA|/ʃʃ/}} (e.g. ''lasciare'' from ''laxare'')
* [[Portuguese language|Portuguese]]: {{IPA|/jʃ/}} (e.g. ''eixo'' from ''axem'')
* [[Romanian language|Romanian]]: {{IPA|/ps/}} (e.g. ''coapsă'' from ''coxa'') and {{IPA|/s/}} (e.g. ''lăsa'' from ''laxare'')
* [[Old Spanish]]: {{IPA|/ʃ/}}
** [[Spanish language|Spanish]]: {{IPA|/x/}} (e.g. ''cuja'' from ''coxa'')
In Old Spanish, {{angbr|x}} came to represent {{IPA|/ʃ/}}, which it still represents in most [[Iberian languages]] and in the orthographies of other languages influenced by Spanish, such as [[Nahuatl language|Nahuatl]]. In French (with a few exceptions), Italian, Romanian, and modern Spanish, {{angbr|x}} was replaced by other letters.

The use of {{angbr|x}} to represent {{IPA|/ks/}} was reintroduced to the Romance languages via Latin [[loanword]]s. In many words, the {{IPA|/ks/}} was [[Consonant voicing and devoicing|voiced]] as {{IPA|/gz/}}.

== Use in writing systems ==
{| class="wikitable mw-collapsible"
|+ Pronunciation of {{angbr|x}} by language
! Orthography
! Phonemes
! Environment
|-
! [[Asturian orthography|Asturian]]
| {{IPAslink|ʃ}}, {{IPA|/ks/}}
|
|-
! [[Afar language|Afar]]
|{{IPAslink|ɖ}}
|
|-
! [[Albanian orthography|Albanian]]
|{{IPAslink|dz}}
|
|-
! [[Azerbaijani alphabet|Azeri]]
|{{IPAslink|x}}
|
|-
! [[Basque orthography|Basque]]
|{{IPAslink|ʃ}}
|
|-
! rowspan="3" |[[Catalan orthography|Catalan]]
|{{IPAslink|ʃ}}
|Usually (word-initially, after consonants, ''i'', ''au'', or ''eu'', in some surnames such as ''[[Rexach]]'')
|-
|{{IPA|/gz/}}
|
|-
|{{IPA|/ks/}}
|
|-
! {{nwr|[[Standard Chinese]]}} ([[Pinyin]])
|{{IPAslink|ɕ}}
|
|-
! [[Tsou language|Cou]]
|{{IPAslink|ɨ}} ~ {{IPAslink|ʉ}}
|
|-
! rowspan="2" | [[Dutch orthography|Dutch]]
|{{IPA|/ks/}}
|Usually, mainly used in loanwords
|-
|{{IPAslink|s}}
|In ''[[Texel]]''
|-
! rowspan="4" | [[English orthography|English]]
|{{IPA|/ks/}}
|Usually; before an unstressed vowel
|-
|{{IPA|/gz/}}
|Before a stressed vowel
|-
|{{IPAslink|z}}
|Word-initially
|-
|{{IPAslink|h}}
|''[[Don Quixote]]'', ''[[Oaxaca]]'', and words derived from [[Classical Nahuatl]]/[[Nahuatl]]
|-
! [[Esperanto orthography|Esperanto]]
|''in digraphs only as a substitute for a diacritic''
|''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]]
|-
! rowspan="5" |[[French orthography|French]]
|{{IPA|/ks/}}
|Usually; in ''[[Aix (disambiguation)#France|Aix-]]'' (prefix or name of several places)
|-
|{{IPA|/gz/}}
|Mainly in the [[prefix]] ex- followed by a vowel; sometimes word-initially
|-
|Silent
|[[Final-obstruent devoicing|Word-finally]] with no liaison
|-
|{{IPAslink|z}}
|Word-finally with [[Liaison (French)|liaison]]; in ''sixième'' (6th) and ''dixième'' (10th)
|-
|{{IPAslink|s}}
|In ''six'' ([[6]]), ''dix'' ([[10]]), ''[[Auxerre]]'', and ''Bruxelles'' ([[Brussels]])
|-
! rowspan="2" |[[Galician alphabet|Galician]]
|{{IPAslink|ʃ}}
|Usually
|-
|{{IPA|/(k)s/}}
|Some learned loanwords
|-
! [[German orthography|German]]
|{{IPA|/ks/}}
|Mainly used in loanwords
|-
! rowspan="2" |[[Indonesian orthography|Indonesian]]
|{{IPAslink|s}}
|In the beginning of a word, mainly used in [[loanword]]s for science
|-
|{{IPA|/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. Mainly used in loanwords for science.
|-
! [[Italian orthography|Italian]]
|{{IPA|/ks/}}
|Mainly used in learned loanwords
|-
! [[Kurdish orthography|Kurdish]]
|{{IPAslink|x}}
|
|-
! [[Lao language|Lao]] romanization
|{{IPAslink|s}}
|A "low consonant", affects the tone of the following vowel
|-
! [[Leonese dialect|Leonese]]
|{{IPAslink|ʃ}}
|
|-
! [[Ligurian language|Ligurian]]
|{{IPAslink|ʒ}}
|
|-
! [[Maltese orthography|Maltese]]
|{{IPAslink|ʃ}}
|
|-
! [[Mayan languages|Mayan]] ([[Academia de Lenguas Mayas de Guatemala|ALMG]])
|{{IPAslink|ʃ}}
|
|-
! [[Nahuatl orthography|Nahuatl]]
|{{IPAslink|ʃ}}
|
|-
! [[Nguni language|Nguni]]
|{{IPAslink|ǁ}}
|
|-
! [[Norwegian orthography|Norwegian]]
|{{IPA|/ks/}}
|Archaic
|-
! rowspan="4" | [[Occitan orthography|Occitan]]
|{{IPAslink|t͡s}}
|Usually
|-
|{{IPAslink|s}}
|Before consonants
|-
|{{IPA|/ɡz/}}
|In the prefix ''ex''- before vowels in the [[Provençal dialect|Provençal]], [[Limousin dialect|Limousin]], [[Auvergnat]], [[Vivaro-Alpine]], and [[Niçard]] dialects
|-
|{{IPA|/ɡʒ/}}
|Before {{angbr|i}} and {{angbr|u}} in the [[Auvergnat]] dialect
|-
! [[Oromo language|Oromo]]
|{{IPAslink|tʼ}}
|
|-
! [[Pirahã language|Pirahã]]
|{{IPAslink|ʔ}}
|
|-
! [[Polish orthography|Polish]]
|{{IPA|/ks ~ gz/}}
|
|-
! rowspan="5" | [[Portuguese orthography|Portuguese]]
|{{IPAslink|ʃ}}
|Usually, always when word-initially
|-
|{{IPA|/ks/}}
|Found between vowels in some words, mainly in those that entered the language recently
|-
|{{IPAslink|s}}
|When preceded by {{angbr|e}} and succeeded by a consonant
|-
|{{IPAslink|z}}
|In the [[prefix]]es {{angbr|ex}} when before a vowel and {{angbr|exo}}
|-
|{{IPA|/gz/}}
|Optionally in the [[prefix]] [[Numeral prefix|''hexa''-]], although most dialects just pronounce this prefix's {{angbr|x}} as {{IPA|/ks/}} or {{IPAslink|z}}
|-
! [[Sardinian alphabet|Sardinian]]
|{{IPAslink|ʒ}}
|
|-
! rowspan="2" |[[Sicilian orthography|Sicilian]]
|{{IPAslink|ʃ}}
|Old Sicilian words and names, e.g. [[Bettino Craxi|''Craxi'']] and [[Joppolo Giancaxio|''Giancaxio'']]
|-
|{{IPA|/k(ə)s(ə)/}}
|Loanwords
|-
! [[Somali orthography|Somali]]
|{{IPAslink|ħ}}
|
|-
! rowspan="3" | [[Spanish orthography|Spanish]]
|{{IPA|/(k)s/}}
|Usually
|-
|{{IPAslink|s}}
|Word-initially
|-
|{{IPAslink|ʃ}}, {{IPAslink|t͡ʃ}}, {{IPAslink|x}}
|In some names and words
|-
! [[Swedish orthography|Swedish]]
|{{IPA|/ks/}}
|
|-
! [[Uzbek alphabet|Uzbek]]
|{{IPAslink|χ}}
|
|-
! rowspan="2" | [[Venetian orthography|Venetian]]
|{{IPAslink|z}}
|Usually
|-
|{{IPAslink|s}}
|In ''Venexia'', "[[Venice]]"
|-
! [[Vietnamese orthography|Vietnamese]]
|{{IPAslink|s}}
|
|}

===English===
In [[English orthography]], {{angbr|x}} is typically pronounced as the voiceless [[consonant cluster]] {{IPAc-en|k|s}} when it follows the stressed vowel (e.g. ''ox''), and the voiced consonant {{IPAc-en|ɡ|z}} when it precedes the stressed vowel (e.g. ''exam''). It is also pronounced {{IPAc-en|ɡ|z}} when it precedes a silent {{angbr|h}} and a stressed vowel (e.g. ''exhaust'').<ref name="Venezky1970">{{cite book|first=Richard|last=Venezky|title=The Structure of English Orthography|url=https://books.google.com/books?id=Mrt_G_RrJykC&pg=PA5|date=1 January 1970|location=[[The Hague]]|publisher=Walter de Gruyter|isbn=978-3-11-080447-8|page=40|access-date=29 October 2016|archive-date=27 April 2017|archive-url=https://web.archive.org/web/20170427105102/https://books.google.com/books?id=Mrt_G_RrJykC&pg=PA5|url-status=live}}</ref> Due to [[yod-coalescence]], the sequence {{angbr|xi}} before a vowel can be pronounced {{IPAc-en|k|ʃ}} resulting from earlier {{IPAc-en|k|s|j}}, e.g. in ''-xion(-)'', ''-xious(-)''. Similarly, the sequence {{angbr|xu}} can be pronounced with {{IPAc-en|k|ʃ}} (e.g. ''flexure'', ''sexual'') or {{IPAc-en|ɡ|ʒ}} (in ''luxury'' and its derivatives).<!-- Oxford gives /ˈlʌkʃ(ə)ri/--> Due to [[NG-coalescence]], the sequence {{angbr|nx}} can be pronounced {{IPAc-en|ŋ|z}} in ''anxiety''.

When {{angbr|x}} ends a word, it is always {{IPAc-en|k|s}} (e.g. ''fax''), except in loan words such as ''faux''. When {{angbr|x}} does start a word, it is usually pronounced 'z' (e.g. ''xylophone'', ''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 {{IPAc-en|s}} (e.g. the obsolete Vietnamese monetary unit ''[[wiktionary:xu|xu]]'') or {{IPAc-en|ʃ}} (e.g. Chinese names starting with ''Xi'', like [[Xiaomi]] or [[Xinjiang]]). Many of the words that start with {{angbr|x}} are of [[Greek language|Greek]] origin, 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 [[Christians|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 disjunction|exclusive-or]], or the [[extinction symbol]]).

X is the [[Letter frequency|third least frequently used letter]] in English (after {{angbr|q}} and {{angbr|z}}), with a frequency of about 0.15% in words.<ref name=":0">{{cite web |last=Mička |first=Pavel |title=Letter frequency (English) |url=http://en.algoritmy.net/article/40379/Letter-frequency-English |website=Algoritmy.net |access-date=9 February 2014 |archive-date=4 March 2021 |archive-url=https://web.archive.org/web/20210304152631/http://en.algoritmy.net/article/40379/Letter-frequency-English |url-status=live }}</ref> There are very few English words that start with {{angbr|x}} (the fewest of any letter).

===Romance languages===
In Latin, {{angbr|x}} stood for {{IPA|/ks/}}. In the [[Romance languages]], as a result of assorted phonetic changes, {{angbr|x}} has other pronunciations:
*In [[Catalan language|Catalan]], {{angbr|x}} has three pronunciations; the most common is {{IPAslink|ʃ}}; as in ''xarop'' ('syrup'). Others are: {{IPA|/ks/}}; ''fixar'' ('to fix'), {{IPA|/ɡz/}}; ''examen''. In addition, {{IPAslink|ʃ}} gets voiced to {{IPAblink|ʒ}} before voiced consonants; ''caixmir''. Catalan also has the digraph {{angbr|tx}}, pronounced {{IPAslink|tʃ}}.
*In [[Galician language|Galician]] and [[Leonese language|Leonese]], {{angbr|x}} is pronounced {{IPAslink|ʃ}} in most cases (often used in place of etymological ''g'' or ''j''). The pronunciation {{IPA|/ks/}} occurs in learned words, such as '<nowiki/>''taxativo''<nowiki/>' (taxing). However, Galician speakers tend to pronounce it {{IPAslink|s}}, especially when it appears before plosives, such as in ''externo'' <nowiki/>('external').
*In [[French language|French]], {{angbr|x}} usually represents {{IPA|/ks/}} or (primarily in words beginning with ex- followed by a vowel) {{IPA|/ɡz/}}. It is pronounced {{IPAslink|s}} in some city names such as ''[[Brussels|Bruxelles]]'' (although some people pronounce it 'ks') or ''[[Auxerre]]''; it is nevertheless pronounced {{IPA|/ks/}} in [[Aix (disambiguation)|Aix]], the name of several towns. At the ends of other words, it is silent (or {{IPAslink|z}} in [[Liaison (French)|liaison]] if the next word starts with a vowel). Two exceptions are pronounced {{IPAslink|s}}: ''six'' ('six') and ''dix'' ('ten'). It is pronounced {{IPAslink|z}} in ''sixième'' and ''dixième''.
*In [[Italian language|Italian]], {{angbr|x}} is either pronounced {{IPA|/ks/}}, as in ''extra'', ''uxorio'', ''xilofono'',<ref>{{cite web |url=http://www.dizionario.rai.it |title=Dizionario di ortografia e pronunzia |trans-title=Dictionary of Spelling and Pronunciation |language=it |website=Dizionario di ortografia e pronunzia |access-date=9 February 2014 |archive-date=16 April 2018 |archive-url=https://web.archive.org/web/20180416110248/http://www.dizionario.rai.it/ |url-status=live }}</ref> or {{IPA|/ɡz/}}, as in ''exogamia'', when it is preceded by {{angbr|e}} and followed by a vowel. In several related languages, notably [[Venetian language|Venetian]], it represents the voiced [[sibilant]] {{IPAslink|z}}. It is also used, mainly amongst young people, as a short written form for "per" (meaning "for"); for example, "x sempre" ("forever"). This is because in Italian, the [[×|multiplication sign]] is called "per". However, {{angbr|x}} is found only in [[loanword]]s, as it is not part of the standard [[Italian alphabet]]; in most words with {{angbr|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''/''[[:it:clacson|clacson]]'').
*In [[Portuguese language|Portuguese]], {{angbr|x}} has four main pronunciations; the most common is {{IPAslink|ʃ}}, as in ''xícara'' ('cup'). The other sounds are: {{IPA|/ks/}} as in ''flexão'' ('flexion'); {{IPAslink|s}}, when preceded by E and followed by a consonant, as in ''contexto'' ({{IPAslink|ʃ}} in European Portuguese), and in a small number of other words, such as ''próximo'' (close/next); and (the rarest) {{IPAslink|z}}, which occurs in the prefix "ex-" before a vowel, as in ''exagerado'' ('exaggerated'). A rare fifth sound is {{IPA|/ɡz/}}, coexisting with {{IPAslink|z}} and {{IPA|/ks/}} as acceptable pronunciations in ''exantema'' and in words with the Greek prefix 'hexa-'.
*In [[Sardinian language|Sardinian]] and [[Ligurian (Romance language)|Ligurian]], {{angbr|x}} represents {{IPAslink|ʒ}}.
*In [[Old Spanish]], {{angbr|x}} was pronounced {{IPAslink|ʃ}}, as it is still currently in other [[Iberian Romance languages]]. Later, the sound evolved to a {{IPAslink|x}} sound. In modern [[Spanish language|Spanish]], due to a spelling reform, whenever {{angbr|x}} is used for the {{IPAslink|x}} sound it has been replaced with {{angbr|j}}, including in words that originally had {{angbr|x}} such as ''ejemplo'' or ''ejercicio'', though {{angbr|x}} is still retained for some names (notably "México", even though "Méjico" may sometimes be used in Spain). Presently, {{angbr|x}} represents the sound {{IPAslink|s}} (word-initially), or the consonant cluster {{IPA|/ks/}} (e.g. ''oxígeno'', ''examen''). Rarely, it can be pronounced {{IPAslink|ʃ}} as in Old Spanish in some proper nouns such as ''Raxel'' (a variant of ''[[Rachel]]'') and ''[[Uxmal]]''.
*In [[Venetian language|Venetian]], {{angbr|x}} represents the voiced alveolar sibilant {{IPAslink|z}}, much like in Portuguese 'exagerado', English 'xylophone' or in the French 'sixième'. Examples from medieval texts include ''raxon'' ('reason'), ''prexon'' ('prison'), ''dexerto'' ('desert'), and ''chaxa'' or ''caxa'' ('home'). Nowadays, the best-known word is ''xe'' (is/are). The most notable exception to this rule is the name ''Venexia'', {{IPA|/veˈnɛsja/}}, in which {{angbr|x}} has evolved from the initial voiced sibilant {{IPAslink|z}} to the present-day voiceless sibilant {{IPAslink|s}}.

===Other languages===
In languages which adopted the [[Latin script|Latin alphabet]] later, {{angbr|x}} is used for various sounds, in some cases inspired by Latin or its descendants, but in others for unrelated consonants. Since the various Romance pronunciations of {{angbr|x}} can often be written in other ways, the letter becomes available for other sounds.
*In [[Albanian language|Albanian]], {{angbr|x}} represents {{IPAslink|dz}} while the [[Digraph (orthography)|digraph]] {{angbr|xh}} represents {{IPAslink|dʒ}}.
*It represents {{IPAslink|x}} ([[voiceless velar fricative]]) in [[Apache]], [[Azerbaijani language|Azerbaijani]], [[Kurdish language|Kurdish]] (Hawar alphabet), [[Georgian language|Georgian]] (when Latinized), [[Lojban]], [[Pashto]] (when Latinized), [[Tatar language|Tatar]] (Jaꞑalif, Zamanälif, official romanization of 2012), [[Uzbek language|Uzbek]], and [[Uyghur language|Uyghur]] ([[Uyghur Latin alphabet|Latin script]]).
*In [[Basque language|Basque]], {{angbr|x}} represents {{IPAslink|ʃ}}. Additionally, the digraph {{angbr|tx}} represents {{IPAslink|tʃ}}.
*In [[Hanyu Pinyin]], [[Standard Chinese]]'s official transcription system in China, Malaysia, Singapore, and Taiwan, the letter {{angbr|x}} represents the [[voiceless alveolo-palatal fricative]] {{IPAslink|ɕ}}, for instance in '[[Xi (surname)|Xi]]', {{IPA|/ɕi/}}.
*In [[Dutch language|Dutch]], {{angbr|x}} usually represents {{IPA|/ks/}}, except in the name of the island of [[Texel]], which is pronounced ''Tessel''. This is because of [[Dutch language#Historical sound changes|historical sound-changes in Dutch]], where all {{IPA|/ks/}} sounds have been replaced by {{IPAslink|s}} sounds. Words with an {{angbr|x}} in the Dutch language are nowadays usually [[loanword]]s. In the [[Languages of Belgium|Dutch-speaking part of Belgium]], [[family name]]s with {{angbr|x}} are not uncommon (e.g. ''Dierckxa'' and ''Hendrickx'').
*In [[Esperanto]], the [[x-convention]] replaces {{angbr|[[ĉ]]}}, {{angbr|[[ĝ]]}}, {{angbr|[[ĥ]]}}, {{angbr|[[ĵ]]}}, {{angbr|[[ŝ]]}}, and {{angbr|[[ŭ]]}} with x-suffixes: {{angbr|cx}}, {{angbr|gx}}, {{angbr|hx}}, {{angbr|jx}}, {{angbr|sx}}, and {{angbr|ux}}.
*In [[German language|German]], generally pronounced {{IPA|/ks/}}; in native words, however, such as ''Ochs'' or ''wachsen'',  the cluster {{IPA|/ks/}} is often written {{angbr|chs}}.
*In transliterations of [[Languages of India|Indian languages]], primarily Indo-Aryan languages, {{angbr|x}} represents the consonant cluster {{IPA|[kʃ]}} in alternate spellings of words containing 'क्ष' (kṣ), especially names such as [[Laxmi]] and [[Dikshit|Dixit]]. Less frequently, {{angbr|x}} is used to represent 'ख़' {{IPAslink|x}}.
*In [[Lao language|Lao]], based on [[romanization of Lao#Consonants|romanization of Lao consonants]], {{angbr|x}} represents {{IPAslink|s}}, while appears to be homophonous with {{angbr|s}}, it is a "low consonant" and affects the tone of the following vowel, e.g. in [[Lan Xang]].
*In [[Maltese language|Maltese]], {{angbr|x}} is pronounced {{IPAslink|ʃ}} or, in some cases, {{IPAslink|ʒ}} (only in loanwords such as 'televixin', and not for all speakers).
*In [[Nahuatl]], {{angbr|x}} represents {{IPAslink|ʃ}}.
*In [[Nguni languages]], {{angbr|x}} represents the [[alveolar lateral click]] {{IPAslink|ǁ}}.
*In [[Norwegian language|Norwegian]], {{angbr|x}} is generally pronounced {{IPA|/ks/}}, but since the 19th century, there has been a tendency to spell it out as {{angbr|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 language|Danish]] and [[Finnish language|Finnish]] is similar (while [[Swedish language|Swedish]], on the other hand, makes frequent use of {{angbr|x}} in native words as well as in loanwords).
*In [[Pirahã language|Pirahã]], {{angbr|x}} symbolizes the [[glottal stop]] {{IPAslink|ʔ}}.
*In [[Polish language|Polish]], {{angbr|x}} was used prior to 19th century both in loanwords and native words and was pronounced {{IPA|/ks/}} or {{IPA|/ɡz/}}, e.g. ''xiążę'', ''xięstwo'' (now ''książę'', ''księstwo''). This was later replaced by {{angbr|ks}} and {{angbr|gz}} in almost all words and remained only in a few loanwords as 'xenia' (''xenien''), surnames as ''Axentowicz'', ''Rexemowski'', and ''Xiężopolski'', names as ''Xawery'', and ''Xymena'', and abbreviations.
*In [[Vietnamese alphabet#Consonants|Vietnamese]], {{angbr|x}} represents {{IPAslink|s}}. This sound was {{IPAblink|ɕ}} in Middle Vietnamese, resembling the Portuguese {{IPAslink|ʃ}}, spelled {{angbr|x}}.

An illustrative example of {{angbr|x}} as a "leftover" letter is the differing usage in three different [[Cushitic languages]]:
*[[Afar language|Afar]]: [[voiced alveolar implosive]] {{IPAslink|ɗ}}
*[[Oromo language|Oromo]]: [[alveolar ejective]] {{IPAslink|tʼ}}
*[[Somali language|Somali]]: [[voiceless pharyngeal fricative]] {{IPAslink|ħ}}

===Other systems===
In the [[International Phonetic Alphabet]], {{angbr IPA|x}} represents a [[voiceless velar fricative]].

==Other uses==
{{main|X (disambiguation)}}

* [[X mark]] has a widely accepted meaning of "negative" or "wrong".
* The [[Roman numeral]] X represents the number 10.<ref>{{cite book |last=Gordon |first=Arthur E. | url=https://archive.org/details/illustratedintro0000gord |url-access=registration |quote=roman numerals. | title=Illustrated Introduction to Latin Epigraphy | publisher=University of California Press | date=1983 | access-date=3 October 2015 | page=[https://archive.org/details/illustratedintro0000gord/page/44 44]|isbn=9780520038981 }}</ref><ref>{{cite book | last=King | first=David A. | url=https://books.google.com/books?id=PapljPXaSbwC&q=roman%20numerals%20letters&pg=PA282 | title=The Ciphers of the Monks | year=2001 | page=282 | publisher=Franz Steiner Verlag | isbn=9783515076401 | quote=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. | access-date=2020-11-22 | archive-date=2021-01-04 | archive-url=https://web.archive.org/web/20210104092429/https://books.google.com/books?id=PapljPXaSbwC&q=roman%20numerals%20letters&pg=PA282 | url-status=live }}</ref>
* 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 (mathematics)|unknown (''incognita'')]] was introduced by [[René Descartes]] in ''[[La Géométrie]]'' (1637).<ref>{{cite book |url=https://books.google.com/books?id=_byqAAAAQBAJ&q=unknown&pg=PA380 |title=A History of Mathematical Notations |first=Florian |last=Cajori |publisher=Open Court Publishing |year=1928 |place=Chicago |page=381 |isbn=9780486161167 |access-date=2020-11-22 |archive-date=2021-04-13 |archive-url=https://web.archive.org/web/20210413173747/https://books.google.com/books?id=_byqAAAAQBAJ&q=unknown&pg=PA380 |url-status=live }} See [[History of algebra#The symbol x|History of algebra]].</ref> 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]]'').
* On some [[Identity document|identification documents]], the letter X represents a [[non-binary gender]], where F means female and M means male.<ref name="Science as Culture">{{cite journal | first = Ingrid | last = Holme | title = Hearing People's Own Stories | journal = Science as Culture | volume = 17 | issue = 3 |pages = 341–344| doi = 10.1080/09505430802280784 | date = 2008 | s2cid = 143528047 }}</ref><ref name="nzpass">{{cite web|url=http://www.passports.govt.nz/Transgender-applicants|title=New Zealand Passports - Information about Changing Sex / Gender Identity|access-date=6 October 2014|url-status = live|archive-url=https://web.archive.org/web/20140923055123/http://www.passports.govt.nz/Transgender-applicants|archive-date=23 September 2014}}</ref>
* 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]], {{char|×}}. In mathematical typesetting, ''x'' meaning an algebraic variable is normally in [[italic type]] (<math>x\!</math>), 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".<ref>{{cite web | url=http://www.dictionary.com/browse/x-marks-the-spot | title=X marks the spot | access-date=21 June 2016 | archive-date=4 June 2016 | archive-url=https://web.archive.org/web/20160604015834/http://www.dictionary.com/browse/x-marks-the-spot | url-status=live }}</ref>
* 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.<ref>{{cite web|url=http://arkitip.com/product/x-mark-of-collaboration-issue-no-0053x/|title=X: Mark of Collaboration - Issue No. 0053X - Arkitip, Inc.|website=arkitip.com|access-date=2016-03-22|archive-date=2016-05-17|archive-url=https://web.archive.org/web/20160517184918/http://arkitip.com/product/x-mark-of-collaboration-issue-no-0053x/|url-status=live}}</ref> This usage mimics the use of a similar mark in [[Hybrid name (botany)|denoting botanical hybrids]], for which scientifically the [[Multiplication sign#Uses|multiplication ×]] is used, but informally, a lowercase "x" is also used.
* {{Anchor|Kiss}}At the end of a letter or other correspondence, '[[Hugs and kisses|x]]' can mean a kiss;<ref>{{Cite news|last=Epstein|first=Nadine|date=2020-10-07|title=A whole lot of history behind 'x' and 'o', kiss and hug|url=https://www.washingtonpost.com/lifestyle/style/a-whole-lot-of-history-behind-x-and-o-kiss-and-hug/2014/02/13/0c3e218a-9341-11e3-b46a-5a3d0d2130da_story.html|url-status=live|access-date=2021-03-12|newspaper=[[The Washington Post]]|archive-date=2018-04-01|archive-url=https://web.archive.org/web/20180401143406/https://www.washingtonpost.com/lifestyle/style/a-whole-lot-of-history-behind-x-and-o-kiss-and-hug/2014/02/13/0c3e218a-9341-11e3-b46a-5a3d0d2130da_story.html}}</ref> the earliest example of this usage cited by the ''[[Oxford English Dictionary]]'' is from 1878.<ref>"[https://www.oed.com/view/Entry/230945 X, n.]" ''OED Online'' (Oxford: Oxford University Press, September 2022), §6. Accessed 11 November 2022.</ref>
* An [[X rating]] denotes media, such as movies, that are intended for adults only.
* In the [[Korean language]], a series of Xs is used as a visual [[bleep censor]] for subtitles and captions, serving the same role as an [[asterisk]] (*).<ref>{{Cite web |title='찐따', 'X랄하다'...욕도 전통을 가진다? |trans-title='loser', 'fXing'... swear words also have a tradition? |url=https://www.goeonair.com/news/article.html?no=13845 |url-status=dead |archive-url=https://web.archive.org/web/20240118155129/https://www.goeonair.com/news/article.html?no=13845 |archive-date=18 January 2024 |access-date=2023-08-22 |website=www.goeonair.com |language=ko}}</ref><ref>{{Cite book |last=참바다 |url=https://books.google.com/books?id=XX4WEAAAQBAJ&dq=%EC%9A%95+X&pg=PA6-IA1 |title=시사칼럼 우리 시대의 상징과 은유 |date=2021-01-15 |publisher=e퍼플 |isbn=979-11-6569-712-9 |language=ko}}</ref>
* 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 System V|Unix]].<ref name=":1" />

==Related characters==
<!-- Please only list characters (symbols in a writing system, but not just convenience code points in Unicode) that are actually related in terms of origin to the letter that is the topic of this article. Characters that merely look subjectively similar need not apply. See https://en.wikipedia.org/wiki/Wikipedia:Verifiability and https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources before adding more. -->

===Descendants and related characters in the Latin alphabet===
*X with [[diacritic]]s: [[Diaeresis (diacritic)|Ẍ ẍ]] [[Ẋ|Ẋ ẋ]] [[X̂|X̂ x̂]] [[ᶍ]]<ref>{{cite web|url=https://www.unicode.org/L2/L2004/04132-n2740-phonetic.pdf|title=L2/04-132 Proposal to add additional phonetic characters to the UCS|date=2004-04-19|first=Peter|last=Constable|access-date=2018-03-24|archive-date=2017-10-11|archive-url=https://web.archive.org/web/20171011014355/http://www.unicode.org/L2/L2004/04132-n2740-phonetic.pdf|url-status=live}}</ref>
*[[International Phonetic Alphabet|IPA]]-specific symbols related to X: {{IPA link|χ}}
*[[Teuthonista]] phonetic transcription-specific symbols related to X:<ref>{{cite web|url=https://www.unicode.org/L2/L2011/11202-n4081-teuthonista.pdf|title=L2/11-202: Revised proposal to encode "Teuthonista" phonetic characters in the UCS|date=2011-06-02|first1=Michael|last1=Everson|first2=Alois|last2=Dicklberger|first3=Karl|last3=Pentzlin|first4=Eveline|last4=Wandl-Vogt|access-date=2018-03-24|archive-date=2017-10-11|archive-url=https://web.archive.org/web/20171011012426/http://www.unicode.org/L2/L2011/11202-n4081-teuthonista.pdf|url-status=live}}</ref>
**{{Unichar|AB56|LATIN SMALL LETTER X WITH LOW RIGHT RING}}
**{{Unichar|AB57|LATIN SMALL LETTER X WITH LONG LEFT LEG}}
**{{Unichar|AB58|LATIN SMALL LETTER X WITH LONG LEFT LEG AND LOW RIGHT RING}}
**{{Unichar|AB59|LATIN SMALL LETTER X WITH LONG LEFT LEG WITH SERIF}}
*{{not a typo|[[ˣ]]}} : Modifier letter small x is used for phonetic transcription
*ₓ : Subscript small x is used in [[Indo-European studies]]<ref>{{cite web|url=https://www.unicode.org/L2/L2004/04191-n2788-laryngeals.pdf|title=L2/04-191: Proposal to encode six Indo-Europeanist phonetic characters in the UCS|date=2004-06-07|first1=Deborah|last1=Anderson|first2=Michael|last2=Everson|access-date=2018-03-24|archive-date=2017-10-11|archive-url=https://web.archive.org/web/20171011014402/http://www.unicode.org/L2/L2004/04191-n2788-laryngeals.pdf|url-status=live}}</ref>

===Ancestors and siblings in other alphabets===
*Χ χ : [[Greek alphabet|Greek]] letter [[Chi (letter)|Chi]], from which the following derive:
**Ꭓ ꭓ : [[Latin chi]]
**Х х : [[Cyrillic]] letter [[Kha (Cyrillic)|Kha]]
**{{Script|Copt|Ⲭ ⲭ}} : [[Coptic alphabet|Coptic]] letter Khe, which derives from Greek Chi
**{{Script|Goth|𐍇}} : [[Gothic alphabet|Gothic]] letter enguz, which derives from Greek Chi
** 𐌗 : [[Old Italic script|Old Italic]] X, which derives from Greek Chi, and is the ancestor of modern Latin X
***{{Script|Runr|ᚷ}} : [[Runes|Runic]] letter [[Gyfu]], which may derive from old Italic X
*Ξ ξ : Greek letter [[Xi (letter)|Xi]], which was used in place of Chi in the Eastern (and the modern) Greek alphabets

==Other representations==
===Computing <span class="anchor" id="Computing codes"></span>===
{{charmap
| 0058 | 0078 | FF38 | FF58 | name1 = Latin Capital Letter X | name2 = Latin Small Letter X | name3 = FULLWIDTH LATIN CAPITAL LETTER X | name4 = FULLWIDTH LATIN SMALL LETTER X
| map1 = [[EBCDIC]] family | map1char1 = E7 | map1char2 = A7
| map2 = [[ASCII]]{{efn|Also for encodings based on ASCII, including the DOS, Windows, ISO-8859 and Macintosh families of encodings.}} | map2char1 = 58 | map2char2 = 78
}}

===Other===
{{Letter other reps
|NATO=Xray<!--not hyphenated "X-ray" -- that's ICAO-->
|Morse=–··–
|Character=X
|Braille=⠭
|fingerspelling=X
}}
{{clear}}

==See also==
*[[X mark]]

==Notes==
{{Notelist}}

==References==
{{Reflist}}

==External links==
*{{Commons-inline}}
*{{Wiktionary-inline|X}}
*{{Wiktionary-inline|x}}
*{{Cite AmCyc|wstitle=X |short=x}}

{{Latin alphabet|X|}}
{{Authority control}}
{{Use dmy dates|date=June 2024}}

[[Category:ISO basic Latin letters]]
[[Category:Cross symbols]]