Xi (letter) Xi (letter) Xi (uppercase Ξ, lowercase ξ; ) is the 14th letter of the Greek alphabet. It is pronounced in Modern Greek, and generally or in English. In the system of Greek numerals, it has a value of 60. Xi was derived from the Phoenician letter samekh . Xi is not to be confused with the letter chi, which gave its form to the Latin letter X. Both in classical Ancient Greek and in Modern Greek, the letter Ξ represents the sound . In some archaic local variants of the Greek alphabet, this letter was missing. Instead, especially in the
History of the alphabet alphabet, in which vowels were accorded equal status with consonants. According to Greek legends transmitted by Herodotus, the alphabet was brought from Phoenicia to Greece by Cadmos. The letters of the Greek alphabet are the same as those of the Phoenician alphabet, and both alphabets are arranged in the same order. However, whereas separate letters for vowels would have actually hindered the legibility of Egyptian, Phoenician, or Hebrew, their absence was problematic for Greek, where vowels played a much more important role. The Greeks used for vowels some of the Phoenician letters representing consonants which weren't used in Greek speech.