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
Letter (alphabet) letters have prescribed orders, although this too may vary by language. In Spanish, for instance, "ñ" is a separate letter, sorted after "n". In English, "n" and "ñ" are classified alike. As symbols that indicate segmental speech, letters are associated with phonetics. In a purely phonemic alphabet, a single phoneme is denoted by a single letter, although in history and in practice letters often indicate more than one phoneme. There are more sounds, or phonemes, in English–about 44–than there are letters of the alphabet. A letter may therefore be associated with more than one phoneme, with the phoneme determined by