1.nounThe 16th letter of the Classical and Modern Greek alphabets and the seventeenth in Old Greek.
2.nounAn irrational and transcendental constant representing the ratio of the circumference of a Euclidean circle to its diameter; approximately 3.14159265358979323846264338327950; usually written π.
3.nounMetal type that has been spilled, mixed together, or disordered.