1841, used in L. 1748 by Swiss mathematician Leonhart Euler (1707-83), from Gk. letter pi (from Heb., lit. "little mouth") as an abbreviation of Gk. periphereia "periphery." For the meaning "printer's term for mixed type," see pie (3).
(pī) An irrational number that has a numerical value of 3.14159265358979... and is represented by the symbol π. It expresses the ratio of the circumference to the diameter of a circle and appears in many mathematical expressions.
The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D. Copyright (C) 2007 by HarperCollins Publishers. Cite This Source
pi in Technology
An interface between Prologapplication programs and the X Window System that aims to be independent from the Prologengine, provided that it has a Quintus foreign function interface (e.g. SICStus and YAP). It is mostly written in Prolog and is divided in two libraries: Edipo - the lower level interface to the Xlib functions; and Ytoolkit - the higher level user interface toolkit. (ftp://ftp.ncc.up.pt/pub/prolog/ytoolkit.tar.Z). E-mail: Ze' Paulo Leal . (1993-03-02)