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
Coptic alphabet of Greek origin; 6 or 7 more were retained from Demotic, depending on the dialect (6 in Sahidic, another each in Bohairic and Akhmimic). In addition to the alphabetic letters, the letter ϯ stood for the syllable or . As the Coptic alphabet is simply a typeface of the Greek alphabet, with a few added letters, it can be used to write Greek without any transliteration schemes. Latin equivalents would include the Icelandic alphabet (which likewise has added letters), or the Fraktur alphabet (which has distinctive forms). While initially unified with the Greek alphabet by Unicode, a proposal was later