Fourteenth letter in the Greek alphabet
Not to be confused with "≡", the
triple bar character, the Cyrillic letter
ksi (Ѯ), or the Arabic letter
ع.
Xi ( ZY or (K)SY;[1][2] uppercase Ξ, lowercase ξ; Greek: ξι) is the fourteenth letter of the Greek alphabet, representing the voiceless consonant cluster [ks]. Its name is pronounced [ksi] in Modern Greek. In the system of Greek numerals, it has a value of 60. Xi was derived from the Phoenician letter samekh 
.
Xi is distinct from the letter chi, which gave its form to the Latin letter X.
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