n The name of the sixteenth letter of the Classical Greek | Classical and Modern Greek alphabets and the seventeenth in Old Greek.
n (mathematics) An irrational and transcendental constant representing the ratio of the circumference of a Euclidean circle to its diameter; approximately 3.1415926535897932384626433832795; usually written π.
n (metal typesetting) Metal type that has been spilled, mixed together, or disordered. Also called pie.
a (typography) Not part of the usual font character set; especially, non-Roman type or symbols as opposed to standard alphanumeric Roman type.