X, or x, is the twenty-fourth and third-to-last
letter
Letter, letters, or literature may refer to:
Characters typeface
* Letter (alphabet), a character representing one or more of the sounds used in speech; any of the symbols of an alphabet.
* Letterform, the graphic form of a letter of the alphabe ...
in the
Latin alphabet
The Latin alphabet or Roman alphabet is the collection of letters originally used by the ancient Romans to write the Latin language. Largely unaltered with the exception of extensions (such as diacritics), it used to write English and the o ...
, used in the
modern English alphabet, the alphabets of other western European languages and others worldwide. Its
name in English is ''"ex"'' (pronounced ), plural ''exes''.
["X", '']Oxford English Dictionary
The ''Oxford English Dictionary'' (''OED'') is the first and foundational historical dictionary of the English language, published by Oxford University Press (OUP). It traces the historical development of the English language, providing a com ...
'', 2nd edition (1989); ''Merriam-Webster's Third New International Dictionary of the English Language, Unabridged'' (1993); "ex", ''op. cit''. X is regularly pronounced as "ks".
History
In
Ancient Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...
, '
Χ' and '
Ψ' were among several variants of the same letter, used originally for and later, in western areas such as
Arcadia
Arcadia may refer to:
Places Australia
* Arcadia, New South Wales, a suburb of Sydney
* Arcadia, Queensland
* Arcadia, Victoria
Greece
* Arcadia (region), a region in the central Peloponnese
* Arcadia (regional unit), a modern administrative un ...
, as a simplification of the
digraph 'ΧΣ' for . In the end, more conservative eastern forms became the standard of
Classical Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...
, and thus 'Χ' ''(
Chi
Chi or CHI may refer to:
Greek
*Chi (letter), the Greek letter (uppercase Χ, lowercase χ);
Chinese
*Chi (length), ''Chi'' (length) (尺), a traditional unit of length, about ⅓ meter
*Chi (mythology) (螭), a dragon
*Chi (surname) (池, pin ...
)'' stood for (later ; palatalized to in Modern Greek before front vowels). However, the
Etruscans
The Etruscan civilization () was developed by a people of Etruria in ancient Italy with a common language and culture who formed a federation of city-states. After conquering adjacent lands, its territory covered, at its greatest extent, rou ...
had taken over 'Χ' from western Greek, and it therefore stands for in Etruscan and
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
.
The letter 'Χ' ~ 'Ψ' for was a Greek addition to the alphabet, placed after the Semitic letters along with ''
phi
Phi (; uppercase Φ, lowercase φ or ϕ; grc, ϕεῖ ''pheî'' ; Modern Greek: ''fi'' ) is the 21st letter of the Greek alphabet.
In Archaic and Classical Greek (c. 9th century BC to 4th century BC), it represented an aspirated voicele ...
'' 'Φ' for .
Pronunciation and use
English
In
English orthography
English orthography is the writing system used to represent spoken English, allowing readers to connect the graphemes to sound and to meaning. It includes English's norms of spelling, hyphenation, capitalisation, word breaks, emphasis, and p ...
, is typically pronounced as the voiceless
consonant cluster
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''. In the education fie ...
when it follows the stressed vowel (e.g. ''ox''), and the voiced consonant when it precedes the stressed vowel (e.g. ''exam''). It is also pronounced when it precedes a silent and a stressed vowel (e.g. ''exhaust'').
Before , or , it can be pronounced or (e.g. ''sexual'' and ''luxury''); these result from earlier and . It also makes the sound in words ending in ''-xion'' (except for ''axion''). When ends a word, it is always (e.g. ''fax''), except in loan words such as ''faux'' (see French, below).
There are very few English words that start with (the fewest of any letter). When 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 (e.g. the obsolete Vietnamese monetary unit ''
xu'') or (e.g. Chinese names starting with Xi like
Xiaomi
Corporation (; ), commonly known as Xiaomi and registered as Xiaomi Inc., is a Chinese designer and manufacturer of consumer electronics and related software, home appliances, and household items. Behind Samsung, it is the second largest ma ...
or
Xinjiang
Xinjiang, SASM/GNC: ''Xinjang''; zh, c=, p=Xīnjiāng; formerly romanized as Sinkiang (, ), officially the Xinjiang Uygur Autonomous Region (XUAR), is an autonomous region of the People's Republic of China (PRC), located in the northwest ...
). Many of the words that start with are of
Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
origin, or standardized trademarks (''
Xerox
Xerox Holdings Corporation (; also known simply as Xerox) is an American corporation that sells print and electronic document, digital document products and services in more than 160 countries. Xerox is headquartered in Norwalk, Connecticut (ha ...
'') 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
The term cross-reference (abbreviation: xref) can refer to either:
* An instance within a document which refers to related information elsewhere in the same document. In both printed and online dictionaries cross-references are important because ...
), "Christ-" (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
Exclusive or or exclusive disjunction is a logical operation that is true if and only if its arguments differ (one is true, the other is false).
It is symbolized by the prefix operator J and by the infix operators XOR ( or ), EOR, EXOR, , , ...
).
X is the
third least frequently used letter in English (after and ), with a frequency of about 0.15% in words.
Other languages
In Latin, stood for . In some languages, as a result of assorted phonetic changes, handwriting adaptations or simply spelling convention, has other pronunciations:
*In
Basque
Basque may refer to:
* Basques, an ethnic group of Spain and France
* Basque language, their language
Places
* Basque Country (greater region), the homeland of the Basque people with parts in both Spain and France
* Basque Country (autonomous co ...
, represents . Additionally there is the digraph .
*In
Dutch
Dutch commonly refers to:
* Something of, from, or related to the Netherlands
* Dutch people ()
* Dutch language ()
Dutch may also refer to:
Places
* Dutch, West Virginia, a community in the United States
* Pennsylvania Dutch Country
People E ...
, usually represents , except in the name of the island of
Texel
Texel (; Texels dialect: ) is a municipality and an island with a population of 13,643 in North Holland, Netherlands. It is the largest and most populated island of the West Frisian Islands in the Wadden Sea. The island is situated north of De ...
, which is pronounced ''Tessel''. This is because of
historical sound-changes in Dutch, where all sounds have been replaced by sounds. Words with an in the Dutch language are nowadays usually
loanword
A loanword (also loan word or loan-word) is a word at least partly assimilated from one language (the donor language) into another language. This is in contrast to cognates, which are words in two or more languages that are similar because th ...
s. In the
Dutch-speaking part of Belgium,
family name
In some cultures, a surname, family name, or last name is the portion of one's personal name that indicates one's family, tribe or community.
Practices vary by culture. The family name may be placed at either the start of a person's full name ...
s with are not uncommon (e.g. Dierckx, Hendrickx, Koninckx, Sterckx, Vranckx).
*In
Norwegian
Norwegian, Norwayan, or Norsk may refer to:
*Something of, from, or related to Norway, a country in northwestern Europe
* Norwegians, both a nation and an ethnic group native to Norway
* Demographics of Norway
*The Norwegian language, including ...
, is generally pronounced , but since the 19th century, there has been a tendency to spell it out as ; it may still be retained in personal names, though it is fairly rare, and occurs mostly in foreign words and
SMS language
Short Message Service (SMS) language, textism, or textese is the abbreviated language and slang commonly used in the late 1990s and early 2000s with mobile phone text messaging, and occasionally through Internet-based communication such as ema ...
. Usage in
Danish
Danish may refer to:
* Something of, from, or related to the country of Denmark
People
* A national or citizen of Denmark, also called a "Dane," see Demographics of Denmark
* Culture of Denmark
* Danish people or Danes, people with a Danish a ...
and
Finnish
Finnish may refer to:
* Something or someone from, or related to Finland
* Culture of Finland
* Finnish people or Finns, the primary ethnic group in Finland
* Finnish language, the national language of the Finnish people
* Finnish cuisine
See also ...
is similar (while
Swedish
Swedish or ' may refer to:
Anything from or related to Sweden, a country in Northern Europe. Or, specifically:
* Swedish language, a North Germanic language spoken primarily in Sweden and Finland
** Swedish alphabet, the official alphabet used by ...
, on the other hand, makes frequent use of in native words as well as in loanwords).
*In
German
German(s) may refer to:
* Germany (of or related to)
** Germania (historical use)
* Germans, citizens of Germany, people of German ancestry, or native speakers of the German language
** For citizens of Germany, see also German nationality law
**Ge ...
, generally pronounced ; in native words, however, such as ''Ochs'' or ''wachsen'', the cluster is often written .
*french: at the ends of words, silent (or in
liaison
Liaison means communication between two or more groups, or co-operation or working together.
Liaison or liaisons may refer to:
General usage
* Affair, an unfaithful sexual relationship
* Collaboration
* Co-operation
Arts and entertainment
* Li ...
if the next word starts with a vowel). Three exceptions are pronounced : ''six'' ("six"), ''dix'' ("ten") and in some city names such as ''
Bruxelles
Brussels (french: Bruxelles or ; nl, Brussel ), officially the Brussels-Capital Region (All text and all but one graphic show the English name as Brussels-Capital Region.) (french: link=no, Région de Bruxelles-Capitale; nl, link=no, Bruss ...
'' (although some people pronounce it 'ks') or ''
Auxerre
Auxerre ( , ) is the capital of the Yonne department and the fourth-largest city in Burgundy. Auxerre's population today is about 35,000; the urban area (''aire d'attraction'') comprises roughly 113,000 inhabitants. Residents of Auxerre are r ...
''; it is fully pronounced in
Aix
Aix or AIX may refer to:
Computing
* AIX, a line of IBM computer operating systems
*An Alternate Index, for a Virtual Storage Access Method Key Sequenced Data Set
* Athens Internet Exchange, a European Internet exchange point
Places Belgi ...
, the name of several towns. It is pronounced in ''sixième'' and ''dixième''. Otherwise or (primarily in words beginning with ex- followed by a vowel) .
*In
Italian
Italian(s) may refer to:
* Anything of, from, or related to the people of Italy over the centuries
** Italians, an ethnic group or simply a citizen of the Italian Republic or Italian Kingdom
** Italian language, a Romance language
*** Regional Ita ...
, is either pronounced , as in ''extra'', ''uxorio'', ''xilofono'', or , as ''exogamia'', when it is preceded by and followed by a vowel. In several related languages, notably Venetian, it represents the voiced sibilant . 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
The multiplication sign, also known as the times sign or the dimension sign, is the symbol , used in mathematics to denote the multiplication operation and its resulting product. While similar to a lowercase X (), the form is properly a four- ...
(similar to ) is called "per". However, is found only in
loanword
A loanword (also loan word or loan-word) is a word at least partly assimilated from one language (the donor language) into another language. This is in contrast to cognates, which are words in two or more languages that are similar because th ...
s, as it is not part of the standard
Italian alphabet
Italian orthography (writing) uses a variant of the Latin alphabet consisting of 21 letters to write the Italian language. This article focuses on the writing of Standard Italian, based historically on the Florentine dialect.
Italian orthography ...
; in most words with , 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
Old Spanish, also known as Old Castilian ( es, castellano antiguo; osp, romance castellano ), or Medieval Spanish ( es, español medieval), was originally a dialect of Vulgar Latin spoken in the former provinces of the Roman Empire that provided ...
, was pronounced , as it is still currently in other
Iberian Romance languages
The Iberian Romance, Ibero-Romance or sometimes Iberian languagesIberian languages is also used as a more inclusive term for all languages spoken on the Iberian Peninsula, which in antiquity included the non-Indo-European Iberian language. are a ...
. Later, the sound evolved to a hard sound. In modern
Spanish
Spanish might refer to:
* Items from or related to Spain:
**Spaniards are a nation and ethnic group indigenous to Spain
**Spanish language, spoken in Spain and many Latin American countries
**Spanish cuisine
Other places
* Spanish, Ontario, Can ...
, due to a spelling reform, whenever is used for the sound it has been replaced with , including in words that originally had such as ''ejemplo'' or ''ejercicio'', though is still retained for some names (notably 'México', even though 'Méjico' may sometimes be used in Spain). Presently, represents the sound (word-initially), or the consonant cluster (e.g. ''oxígeno, examen''). Rarely, it can be pronounced as in Old Spanish in some proper nouns such as 'Raxel' (a variant of
Rachel
Rachel () was a Biblical figure, the favorite of Jacob's two wives, and the mother of Joseph and Benjamin, two of the twelve progenitors of the tribes of Israel. Rachel's father was Laban. Her older sister was Leah, Jacob's first wife. Her aun ...
) and ''
Uxmal
Uxmal (Yucatec Maya: ''Óoxmáal'' ) is an ancient Maya city of the classical period located in present-day Mexico. It is considered one of the most important archaeological sites of Maya culture, along with Palenque, Chichen Itza and Calakmul i ...
''.
*In
Galician and
Leonese, is pronounced in most cases (often used in place of etymological ''g'' or ''j''). The pronunciation occurs in learned words, such as '
''taxativo''
' (taxing). However, Galician speakers tend to pronounce it , especially when it appears before plosives, such as in externo''
' (external).
*In
Catalan
Catalan may refer to:
Catalonia
From, or related to Catalonia:
* Catalan language, a Romance language
* Catalans, an ethnic group formed by the people from, or with origins in, Northern or southern Catalonia
Places
* 13178 Catalan, asteroid #1 ...
, has three sounds; the most common is ; as in 'xarop' (syrup). Other sounds are: ; 'fixar' (to fix), ; 'examen'. In addition, gets voiced to before voiced consonants; 'caixmir'. Catalan also has the digraph , pronounced .
*In
Portuguese
Portuguese may refer to:
* anything of, from, or related to the country and nation of Portugal
** Portuguese cuisine, traditional foods
** Portuguese language, a Romance language
*** Portuguese dialects, variants of the Portuguese language
** Portu ...
, has four main sounds; the most common is , as in 'xícara' (cup). The other sounds are: as in 'flexão' (flexion); , when preceded by E and followed by a consonant, as in 'contexto' ( in European Portuguese), and in a small number of other words, such as 'próximo' (close/next); and (the rarest) , which occurs in the prefix 'ex-' before a vowel, as in 'exagerado' (exaggerated). A rare fifth sound is , coexisting with and as acceptable pronunciations in ''exantema'' and in words with the Greek prefix 'hexa-'.
*In
Sardinian and
Ligurian, X represents .
*In
Venetian, it represents the voiced alveolar sibilant much like in Portuguese 'exagerado', English 'xylophone' or in the French 'sixième'. Examples from medieval texts include ''raxon'' (reason), ''prexon'' (prison), ''dexerto'' (desert), ''chaxa'' or ''caxa'' (home). Nowadays, the best-known word is ''xe'' (is/are). The most notable exception to this rule is the name ''Venexia'' in which has evolved from the initial voiced sibilant to the present day voiceless sibilant.
*In
Albanian
Albanian may refer to:
*Pertaining to Albania in Southeast Europe; in particular:
**Albanians, an ethnic group native to the Balkans
**Albanian language
**Albanian culture
**Demographics of Albania, includes other ethnic groups within the country ...
, represents , while the
digraph represents .
*In
Maltese, is pronounced or, in some cases, (only in loanwords such as 'televixin', and not for all speakers).
*In
Polish
Polish may refer to:
* Anything from or related to Poland, a country in Europe
* Polish language
* Poles
Poles,, ; singular masculine: ''Polak'', singular feminine: ''Polka'' or Polish people, are a West Slavic nation and ethnic group, w ...
, was used prior to 19th century both in loanwords and native words and was pronounced or , e.g. ''xiążę'', ''xięstwo'' (now ''książę'', ''księstwo''). Later was replaced by and in almost all words and remained only in a few loanwords as 'xenia' (xenien), surnames as Axentowicz, Jaxa, Koxowski, Mixtacki, Rexemowski, Xiężopolski, names as Xawery, Xymena and abbreviations.
Additionally, in languages for which the
Latin alphabet
The Latin alphabet or Roman alphabet is the collection of letters originally used by the ancient Romans to write the Latin language. Largely unaltered with the exception of extensions (such as diacritics), it used to write English and the o ...
has been adapted only recently, 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 can be written by other means, the letter becomes available for more unusual sounds.
* represents (
voiceless velar fricative
The voiceless velar fricative is a type of consonantal sound used in some spoken languages. It was part of the consonant inventory of Old English and can still be found in some dialects of English, most notably in Scottish English, e.g. in ''loc ...
) in e.g.
Azerbaijani,
Kurdish
Kurdish may refer to:
*Kurds or Kurdish people
*Kurdish languages
*Kurdish alphabets
*Kurdistan, the land of the Kurdish people which includes:
**Southern Kurdistan
**Eastern Kurdistan
**Northern Kurdistan
**Western Kurdistan
See also
* Kurd (dis ...
(Hawar alphabet),
Georgian
Georgian may refer to:
Common meanings
* Anything related to, or originating from Georgia (country)
** Georgians, an indigenous Caucasian ethnic group
** Georgian language, a Kartvelian language spoken by Georgians
**Georgian scripts, three scrip ...
(when Latinized),
Lojban
Lojban (pronounced ) is a logical, constructed, human language created by the Logical Language Group which aims to be syntactically unambigious. It succeeds the Loglan project.
The Logical Language Group (LLG) began developing Lojban in 1987. ...
,
Pashto
Pashto (,; , ) is an Eastern Iranian language in the Indo-European language family. It is known in historical Persian literature as Afghani ().
Spoken as a native language mostly by ethnic Pashtuns, it is one of the two official languages ...
(when Latinized),
Tatar
The Tatars ()[Tatar]
in the Collins English Dictionary is an umbrella term for different (Jaꞑalif, Zamanälif, official romanization of 2012),
Uzbek, and
Uyghur (
Latin script
The Latin script, also known as Roman script, is an alphabetic writing system based on the letters of the classical Latin alphabet, derived from a form of the Greek alphabet which was in use in the ancient Greek city of Cumae, in southern Italy ...
).
*
Esperanto
Esperanto ( or ) is the world's most widely spoken constructed international auxiliary language. Created by the Warsaw-based ophthalmologist L. L. Zamenhof in 1887, it was intended to be a universal second language for international communi ...
: The
x-convention
There are two conventional sets ASCII substitutions for the letters in the Esperanto alphabet that have diacritics, as well as a number of graphic work-arounds.
The diacritics of Esperanto were designed with a French manual typewriter in mind, as ...
replaces , , , , , and with x-suffixes: , , , , , and .
*In transliteration of
Indian languages, primarily Indo-Aryan languages, represents the consonant cluster in alternate spellings of words containing 'क्ष' (kṣ), especially names such as
Laxmi and
Dixit. Less frequently, is used to represent 'ख़' .
*In
Apache
The Apache () are a group of culturally related Native American tribes in the Southwestern United States, which include the Chiricahua, Jicarilla, Lipan, Mescalero, Mimbreño, Ndendahe (Bedonkohe or Mogollon and Nednhi or Carrizaleño an ...
represents
*In
Nahuatl
Nahuatl (; ), Aztec, or Mexicano is a language or, by some definitions, a group of languages of the Uto-Aztecan language family. Varieties of Nahuatl are spoken by about Nahua peoples, most of whom live mainly in Central Mexico and have smaller ...
, represents .
*In
Nguni languages
The Nguni languages are a group of closely related Bantu languages spoken in southern Africa by the Nguni peoples. Nguni languages include Xhosa, Zulu, Ndebele (sometimes referred to as "Northern Ndebele"), and Swazi. The appellation "Nguni" d ...
, represents the
alveolar lateral click .
*In
Pirahã, symbolizes the
glottal stop
The glottal plosive or stop is a type of consonantal sound used in many spoken languages, produced by obstructing airflow in the vocal tract or, more precisely, the glottis. The symbol in the International Phonetic Alphabet that represents thi ...
.
*An illustrating example of "x" as a "leftover" letter is differing usage in three different
Cushitic languages
The Cushitic languages are a branch of the Afroasiatic language family. They are spoken primarily in the Horn of Africa, with minorities speaking Cushitic languages to the north in Egypt and the Sudan, and to the south in Kenya and Tanzania. As ...
:
**
Afar:
voiced alveolar implosive
The voiced alveolar implosive is a type of consonantal sound, used in some spoken languages. The symbol in the International Phonetic Alphabet
The International Phonetic Alphabet (IPA) is an alphabetic system of phonetic notation based ...
**
Oromo:
alveolar ejective
**
Somali:
voiceless pharyngeal fricative
The voiceless pharyngeal fricative is a type of consonantal sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is an h-bar, , and the equivalent X-SAMPA symbol is X\. In the trans ...
*In East and Asia:
**In
Lao, based on
romanization of Lao consonants, may represent , e.g. in
Lan Xang
existed as a unified kingdom from 1353 to 1707.
For three and a half centuries, Lan Xang was one of the largest kingdoms in Southeast Asia. The meaning of the kingdom's name alludes to the power of the kingship and formidable war machine of the ea ...
.
**In
Vietnamese
Vietnamese may refer to:
* Something of, from, or related to Vietnam, a country in Southeast Asia
** A citizen of Vietnam. See Demographics of Vietnam.
* Vietnamese people, or Kinh people, a Southeast Asian ethnic group native to Vietnam
** Overse ...
, is pronounced like English (at the beginning of a word, e.g. "sing"). This sound was in Middle Vietnamese, resembling the Portuguese sound , spelled .
**In
Hanyu Pinyin
Hanyu Pinyin (), often shortened to just pinyin, is the official romanization system for Standard Mandarin Chinese in China, and to some extent, in Singapore and Malaysia. It is often used to teach Mandarin, normally written in Chinese for ...
,
Standard Chinese
Standard Chinese ()—in linguistics Standard Northern Mandarin or Standard Beijing Mandarin, in common speech simply Mandarin, better qualified as Standard Mandarin, Modern Standard Mandarin or Standard Mandarin Chinese—is a modern Standar ...
's official transcription system in China, Malaysia, Singapore, and Taiwan, the letter represents the
voiceless alveolo-palatal fricative
The voiceless alveolo-palatal sibilant fricative is a type of consonantal sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ("c", plus the curl also found in its voiced counterp ...
, for instance in '
Xi', .
Other systems
In the
International Phonetic Alphabet
The International Phonetic Alphabet (IPA) is an alphabetic system of phonetic transcription, phonetic notation based primarily on the Latin script. It was devised by the International Phonetic Association in the late 19th century as a standa ...
, represents a
voiceless velar fricative
The voiceless velar fricative is a type of consonantal sound used in some spoken languages. It was part of the consonant inventory of Old English and can still be found in some dialects of English, most notably in Scottish English, e.g. in ''loc ...
.
Other uses
In
mathematics
Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern 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
René Descartes ( or ; ; Latinized: Renatus Cartesius; 31 March 1596 – 11 February 1650) was a French philosopher, scientist, and mathematician, widely considered a seminal figure in the emergence of modern philosophy and science. Mathem ...
in ''
La Géométrie
''La Géométrie'' was published in 1637 as an appendix to ''Discours de la méthode'' (''Discourse on the Method''), written by René Descartes. In the ''Discourse'', he presents his method for obtaining clarity on any subject. ''La Géométrie ...
'' (1637). As a result of its use in
algebra
Algebra () is one of the broad areas of mathematics. Roughly speaking, algebra is the study of mathematical symbols and the rules for manipulating these symbols in formulas; it is a unifying thread of almost all of mathematics.
Elementary a ...
, X is often used to represent unknowns in other circumstances (e.g.
X-rays
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 Picometre, picometers to 10 Nanometre, nanometers, corresponding to frequency, ...
,
Generation X
Generation X (or Gen X for short) is the Western world, Western demographic Cohort (statistics), cohort following the baby boomers and preceding the millennials. Researchers and popular media use the mid-to-late 1960s as starting birth years a ...
, ''
The X-Files
''The X-Files'' is an American science fiction on television, science fiction drama (film and television), drama television series created by Chris Carter (screenwriter), Chris Carter. The series revolves around Federal Bureau of Investigation ...
'', and ''
The Man from Planet X
''The Man from Planet X'' is a 1951 independently made American black-and-white science fiction horror film, produced by Jack Pollexfen and Aubrey Wisberg, directed by Edgar G. Ulmer, that stars Robert Clarke, Margaret Field, and William Sch ...
''; see also
Malcolm X
Malcolm X (born Malcolm Little, later Malik el-Shabazz; May 19, 1925 – February 21, 1965) was an American Muslim minister and human rights activist who was a prominent figure during the civil rights movement. A spokesman for the Nation of Is ...
).
On some identification documents, the letter X represents a
non-binary gender
Non-binary and genderqueer are umbrella terms for gender identities that are not solely male or femaleidentities that are outside the gender binary. Non-binary identities fall under the transgender umbrella, since non-binary people typicall ...
, where F means female and M means male.
In the
Cartesian coordinate system
A Cartesian coordinate system (, ) in a plane is a coordinate system that specifies each point uniquely by a pair of numerical coordinates, which are the signed distances to the point from two fixed perpendicular oriented lines, measured in t ...
, ''x'' is used to refer to the horizontal axis.
It is also sometimes used as a
typographic approximation for the
multiplication sign
The multiplication sign, also known as the times sign or the dimension sign, is the symbol , used in mathematics to denote the multiplication operation and its resulting product. While similar to a lowercase X (), the form is properly a four- ...
, . In mathematical typesetting, ''x'' meaning an algebraic variable is normally in
italic type
In typography, italic type is a cursive font based on a stylised form of calligraphic handwriting. Owing to the influence from calligraphy, italics normally slant slightly to the right. Italics are a way to emphasise key points in a printed tex ...
(
), 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".
The
Roman numeral
Roman numerals are a numeral system that originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages. Numbers are written with combinations of letters from the Latin alphabet, ea ...
X represents the number
10.
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. 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; the earliest example of this usage cited by the ''Oxford English Dictionary'' is from 1878.
An
X rating
An X rating is a rating used in various countries to classify films that have content deemed suitable only for adults. It is used when the violent or sexual content of a film is considered to be potentially disturbing to general audiences.
Aust ...
denotes media such as movies that are intended for adults only.
Related characters
Descendants and related characters in the Latin alphabet
*X with
diacritic
A diacritic (also diacritical mark, diacritical point, diacritical sign, or accent) is a glyph added to a letter or to a basic glyph. The term derives from the Ancient Greek (, "distinguishing"), from (, "to distinguish"). The word ''diacriti ...
s:
Ẍ ẍ Ẋ ẋ X̂ x̂ ᶍ
*
IPA
IPA commonly refers to:
* India pale ale, a style of beer
* International Phonetic Alphabet, a system of phonetic notation
* Isopropyl alcohol, a chemical compound
IPA may also refer to:
Organizations International
* Insolvency Practitioners ...
-specific symbols related to X:
*
Teuthonista
Teuthonista is a phonetic transcription system used predominantly for the transcription of (High) German dialects. It is very similar to other Central European transcription systems from the early 20th century. The base characters are mostly bas ...
phonetic transcription-specific symbols related to X:
**
**
**
**
*
ˣ : Modifier letter small x is used for phonetic transcription
*ₓ : Subscript small x is used in
Indo-European studies
Indo-European studies is a field of linguistics and an interdisciplinary field of study dealing with Indo-European languages, both current and extinct. The goal of those engaged in these studies is to amass information about the hypothetical pro ...
Ancestors and siblings in other alphabets
*Χ χ :
Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
letter
Chi
Chi or CHI may refer to:
Greek
*Chi (letter), the Greek letter (uppercase Χ, lowercase χ);
Chinese
*Chi (length), ''Chi'' (length) (尺), a traditional unit of length, about ⅓ meter
*Chi (mythology) (螭), a dragon
*Chi (surname) (池, pin ...
, from which the following derive:
**Х х :
Cyrillic
, bg, кирилица , mk, кирилица , russian: кириллица , sr, ћирилица, uk, кирилиця
, fam1 = Egyptian hieroglyphs
, fam2 = Proto-Sinaitic
, fam3 = Phoenician
, fam4 = G ...
letter
Kha
** :
Coptic
Coptic may refer to:
Afro-Asia
* Copts, an ethnoreligious group mainly in the area of modern Egypt but also in Sudan and Libya
* Coptic language, a Northern Afro-Asiatic language spoken in Egypt until at least the 17th century
* Coptic alphabet ...
letter Khe, which derives from Greek Chi
** :
Gothic
Gothic or Gothics may refer to:
People and languages
*Goths or Gothic people, the ethnonym of a group of East Germanic tribes
**Gothic language, an extinct East Germanic language spoken by the Goths
**Crimean Gothic, the Gothic language spoken b ...
letter enguz, which derives from Greek Chi
** 𐌗 :
Old Italic X, which derives from Greek Chi, and is the ancestor of modern Latin X
*** :
Runic
Runes are the letters in a set of related alphabets known as runic alphabets native to the Germanic peoples. Runes were used to write various Germanic languages (with some exceptions) before they adopted the Latin alphabet, and for specialised ...
letter
Gyfu
Gyfu is the name for the ''g''-rune in the Anglo-Saxon rune poem, meaning ‘gift’ or ‘generosity’:
The corresponding letter of the Gothic alphabet is 𐌲 ''g'', called ''giba''. The same rune also appears in the Elder Futhark, with a ...
, 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
Computing codes
:
1
In the
C programming language
''The C Programming Language'' (sometimes termed ''K&R'', after its authors' initials) is a computer programming book written by Brian Kernighan and Dennis Ritchie, the latter of whom originally designed and implemented the language, as well as ...
, "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.
Other representations
See also
*
X mark
An X mark (also known as an ex mark or a cross mark or simply an X or ex or a cross) is used to indicate the concept of negation (for example "no, this has not been verified", "no, that is not the correct answer" or "no, I do not agree") as well ...
*
X.com
X.com was an online bank co-founded by Elon Musk, Harris Fricker, Christopher Payne, and Ed Ho in 1999 in Palo Alto, California. In 2000, X.com merged with competitor Confinity Inc., a software company also based in Palo Alto. Musk was attracte ...
References
External links
*
*
*
*
{{Authority control
ISO basic Latin letters
Cross symbols