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 Greek alphabet the Latin alphabet. Most specialists believe that the Phoenician alphabet was adopted for Greek during the early 8th century BC, perhaps in Euboea. The earliest known fragmentary Greek inscriptions date from this time, 770–750 BC, and they match Phoenician letter forms of c. 800–750 BC. The oldest substantial texts known to date are the Dipylon inscription and the text on the so-called Cup of Nestor, both dated to the late 8th century BC, inscriptions of personal ownership and dedications to a god. Tradition recounts that a daughter of a certain Agamemnon, king of Aeolian Cyme, married a Phrygian king called