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 many letters the Proto-Sinaitic alphabet had nor what their alphabetic order was. Among its descendants, the Ugaritic alphabet had 27 consonants, the South Arabian alphabets had 29, and the Phoenician alphabet 22. These scripts were arranged in two orders, an "ABGDE" order in Phoenician and an "HMĦLQ" order in the south; Ugaritic preserved both orders. Both sequences proved remarkably stable among the descendants of these scripts. The letter names proved stable among the many descendants of Phoenician, including Samaritan, Aramaic, Syriac, Arabic, Hebrew, and Greek alphabet. However, they were largely abandoned in Tifinagh, Latin and Cyrillic. The letter sequence continued