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
Romanization of Greek Romanization of Greek Romanization of Greek is the transliteration (letter-mapping) or transcription (sound-mapping) of text from the Greek alphabet into the Latin alphabet. The conventions for writing and romanizing Ancient Greek and Modern Greek differ markedly, which can create confusion. The sound of the English letter B () was written as in ancient Greek but is now written as the digraph , while the modern sounds like the English letter V () instead. The Greek name became Johannes in Latin and then John in English, but in Greek itself has instead become ; this might be written as Yannis, Jani,