PI


Meaning of PI in English

n. 1 the sixteenth letter of the Greek alphabet. 2 (as π.) the symbol of the ratio of the circumference of a circle to its diameter (approx. 3.14159). pi-meson = PION.

[ Gk: sense 2 f. Gk periphereia circumference ]

Concise Oxford English dictionary.      Краткий оксфордский словарь английского языка.