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
Latin alphabet alphabets may discard letters, like the Rotokas alphabet, or add new letters, like the Danish and Norwegian alphabets. Letter shapes have evolved over the centuries, including the development in Medieval Latin of lower-case, forms which did not exist in the Classical period alphabet. English is the only major modern European language requiring no diacritics for native words (although a diaeresis may be used in words such as "coöperation"). It is generally believed that the Romans adopted the Cumae alphabet, a variant of the Greek alphabet, in the 7th century BC from Cumae, a Greek colony in Southern Italy. (Gaius Julius