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 table2 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