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Greek alphabet | |||||
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Αα Alpha | Νν Nu | ||||
Ββ Beta | Ξξ Xi | ||||
Γγ Gamma | Οο Omicron | ||||
Δδ Delta | Ππ Pi | ||||
Εε Epsilon | Ρρ Rho | ||||
Ζζ Zeta | Σσς Sigma | ||||
Ηη Eta | Ττ Tau | ||||
Θθ Theta | Υυ Upsilon | ||||
Ιι Iota | Φφ Phi | ||||
Κκ Kappa | Χχ Chi | ||||
Λλ Lambda | Ψψ Psi | ||||
Μμ Mu | Ωω Omega | ||||
Obsolete letters | |||||
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Other characters | |||||
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Greek diacritics |
Chi (uppercase Χ, lowercase χ; Greek: Χι [xiː] He) is the 22nd letter of the Greek alphabet, pronounced as [kai] in English. Its value in Ancient Greek was an aspirated velar stop /kʰ/ (in the Western Greek alphabet: /ks/).
In Koine Greek and later dialects it became a fricative along with Θ and Φ. In Modern Greek, is has two distinct pronunciations: In front of high or front vowels (e, i, oi, ai, y) it is pronounced as a voiceless palatal fricative [ç], as in German ich or like the 'h' in some pronunciations of the English words 'hew' and 'human'. In front of low or back vowels (a, o, ou) and consonants, it is pronounced as a voiceless uvular fricative [χ].
In the system of Greek numerals it has a value of 600.
In ancient times, some dialects of Greek used the chi instead of xi to represent the /ks/ sound. This was borrowed into the early Latin language, which led to the letter X being used for the same sound in Latin, and the modern languages which use the Latin alphabet.
Chi was also included in the Cyrillic alphabet as the letter Х, with the phonetic value /x/ or /h/.
Chi is the basis for the name Chiastic structure and the name of Chiasmus.
In Plato's Timaeus, it is explained that the two bands which form the soul of the world cross each other like the letter Χ.
Chi or X is often used to abbreviate the name Christ, as in the holiday Christmas (Xmas).
The optic chiasm, an x-shaped connection of the optic nerves leading to the eye, got its name from the letter chi because of its shape; [1] likewise, the shape of the letter chi is the origin of the rhetorical device chiasmus.
In Chemistry Chi refers to the mole fraction in a mixture.