X

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Basic Latin alphabet
  Aa Bb Cc Dd  
Ee Ff Gg Hh Ii Jj
Kk Ll Mm Nn Oo Pp
Qq Rr Ss Tt Uu Vv
  Ww Xx Yy Zz  

X is the twenty-fourth letter in the modern Latin alphabet. Its name in English is pronounced eks (/ɛks/).

In phonetics, x is the IPA and X-SAMPA symbol for the voiceless velar fricative (IPA is used for pronunciation throughout this article).

Contents

  • 1 History
  • 2 Usage
  • 3 Codes for computing
  • 4 See also
  • 5 Other uses for the letter X

[edit] History

An x.

The consonant cluster /ks/ was, in Ancient Greek, written as either Chi Χ (Western Greek) or Xi Ξ (Eastern Greek). In the end, Chi was standardized as /kʰ/ (/x/ in Modern Greek), while Xi was standardized for /ks/. But the Etruscans had taken over Χ from older Western Greek; therefore, it stood for /ks/ in Etruscan and Latin.

It is unknown whether the letters Chi and Xi are Greek inventions, or whether they are ultimately of Semitic origin. Chi was placed toward the end of the Greek alphabet, after the Semitic letters, along with Phi, Psi, and Omega, suggesting that it was an innovation; further, there is no letter corresponding specifically to the sound /ks/ in Semitic. There was a Phoenician letter kheth with a probable sound /ħ/, somewhat similar to /kʰ/, but this was adopted into Greek as first the consonant /h/, and later, the long vowel Eta (Η,η), and does not seem to have been the source of Greek Chi. The Phoenician letter Samekh (representing /s/) is usually considered the inspiration for Greek Xi, but as noted, Chi had a graphically distinct shape from Xi — although it may possibly have been another variant originally based on samekh. The original form of samekh may have been an Egyptian hieroglyph for the Djed column, but this too is uncertain, as no intervening Proto-Sinaitic form of this letter is attested.

Egyptian hieroglyph "column" Phoenician S Greek Xi Greek Chi Etruscan X
R11

[edit] Usage

In some languages, as a result of assorted phonetic changes and handwriting adaptations, X has other pronunciations:

No words in the Basic English vocabulary begin with X, but it occurs in words beginning with other letters. It is often found in a word with an E before it. Otherwise it is the third most rarely used letter in the English language.

[edit] Codes for computing

Alternative representations of X
NATO phonetic Morse code
X-ray –··–
Signal flag Semaphore ASL Manual Braille

In Unicode the capital X is codepoint U+0058 and the lowercase x is U+0078.

The ASCII code for capital X is 88 and for lowercase x is 120; or in binary 01011000 and 01111000, correspondingly.

The EBCDIC code for capital X is 231 and for lowercase x is 167.

The numeric character references in HTML and XML are "X" and "x" for upper and lower case respectively.