Phi (letter)


Phi (uppercase Φ, lowercase φ), pronounced // ("fee") in modern Greek and sometimes as // (as in "defy") in English, is the 21st letter of the Greek alphabet. In modern Greek, it represents [], a voiceless labiodental fricative. In Ancient Greek it represented [], an aspirated voiceless bilabial plosive. In the system of Greek numerals it has a value of 500 (φʹ) or 500,000 (͵φ).