Psi (letter) Psi (letter) Psi (; uppercase ', lowercase '; "psi" ) is the 23rd letter of the Greek alphabet and has a numeric value of 700. In both Classical and Modern Greek, the letter indicates the combination /ps/ (as in English word "lapse"). For Greek loanwords in Latin and modern languages with Latin alphabets, psi is usually transliterated as "ps". The letter's origin is uncertain. It may or may not derive from the Phoenician alphabet. It appears in the 7th century BC, expressing /ps/ in the Eastern alphabets, but /kʰ/ in the Western alphabets (the sound expressed by Χ in the
History of the alphabet letters G, J, U, W, Y, and Z, as well as some other differences. C, K, and Q in the Roman alphabet could all be used to write both the and sounds; the Romans soon modified the letter C to make G, inserted it in seventh place, where Z had been, to maintain the gematria (the numerical sequence of the alphabet). Over the few centuries after Alexander the Great conquered the Eastern Mediterranean and other areas in the third century BCE, the Romans began to borrow Greek words, so they had to adapt their alphabet again in order to write