Main Entry: ¹pi

Pronunciation: \ˈpī\

Function: noun

Inflected Form(s): plural pis \ˈpīz\

Etymology: Middle Greek, from Greek pei, of Semitic origin; akin to Hebrew pē pe

Date: 1638

1 : the 16th letter of the Greek alphabet — see alphabet table
2 a : the symbol π denoting the ratio of the circumference of a circle to its diameter b : the ratio itself : a transcendental number having a value rounded to eight decimal places of 3.14159265