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 Greeks. From the Etruscans, a tribe living in the first millennium BCE in central Italy, and the Western Greeks, the Latins adopted writing in about the seventh century. In adopting writing from these two groups, the Latins dropped four characters from the Western Greek alphabet. They also adapted the Etruscan letter F, pronounced 'w,' giving it the 'f' sound, and the Etruscan S, which had three zigzag lines, was curved to make the modern S. To represent the G sound in Greek and the K sound in Etruscan, the Gamma was used. These changes produced the modern alphabet without the