Chi (letter) for the design of steel structures. In graph theory, a lowercase chi is used to represent a graph's chromatic number. Chi (letter) Chi (uppercase Χ, lowercase χ; ) is the 22nd letter of the Greek alphabet, pronounced or in English. Its value in Ancient Greek was an aspirated velar stop (in the Western Greek alphabet: /ks/). In Koine Greek and later dialects it became a fricative (/) along with Θ and Φ. In Modern Greek, it has two distinct pronunciations: In front of high or front vowels ( or ) it is pronounced as a voiceless palatal fricative , as
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.