pi

pi · noun

imported

Definitions

noun

  1. 1.

    The sixteenth letter of the Greek alphabet (uppercase Pi, lowercase pi), transliterated as 'p'.

  2. 2.

    (Mathematics) The ratio of a circle's circumference to its diameter, approximately equal to 3.14159.

Phrases & expressions

  • •
    Pi Day — March 14 (3/14), celebrated by mathematics enthusiasts.

Related words

See also: circle, circumference, diameter, radius

Etymology

From Greek pi, the sixteenth letter of the Greek alphabet. The mathematical use derives from the first letter of Greek periphereia ("circumference").