Chi is the 22nd letter of the Greek alphabet, pronounced /ˈkaɪ/ or /ˈkiː/ in English.
In Plato's Timaeus, it is explained that the two bands that 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). When fused within a single typespace with the Greek letter Rho, it is called the labarum and used to represent the person of Jesus Christ.
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