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 Arabic alphabet History of the Arabic alphabet The history of the Arabic alphabet concerns the origins and the evolution of the Arabic script. It is thought that the Arabic alphabet is a derivative of the Nabataean variation of the Aramaic alphabet, which descended from the Phoenician alphabet, which, among others, gave rise to the Hebrew alphabet and the Greek alphabet (and therefore the Cyrillic and Roman alphabets). The Arabic alphabet evolved either from the Nabataean, or (less widely believed) directly from the Syriac. This table shows changes undergone by the shapes of the letters from the Aramaic original to the Nabataean and