pi

1 [pahy]
noun, plural pis.
1.
the 16th letter of the greek alphabet (II, π).
2.
the consonant sound represented by this letter.
3.
Mathematics.
a.
the letter π, used as the symbol for the ratio of the circumference of a circle to its diameter.
b.
the ratio itself: 3.141592+.

Origin:
1835–45; < Greek pî, peî; used in mathematics to represent Greek periphérion periphery

Dictionary.com Unabridged

pi

2 [pahy]
noun, plural pies.
1.
printing types mixed together indiscriminately.
2.
any confused mixture; jumble.
verb (used with object), pied, piing.
3.
to reduce (printing types) to a state of confusion.
4.
to jumble.
Also, pie.


Origin:
1650–60; origin uncertain

PI

1.
Law. personal injury.
2.
principal investigator.
3.
Also, P.I., p.i. private investigator.

Pi.

Also, pi.

P.I.

1.
Philippine Islands.
2.
Also, PI, p.i. private investigator.
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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Collins
World English Dictionary
pi1 (paɪ)
 
n , pl pis
1.  the 16th letter in the Greek alphabet (Π, π), a consonant, transliterated as p
2.  maths a transcendental number, fundamental to mathematics, that is the ratio of the circumference of a circle to its diameter. Approximate value: 3.141 592…; symbol: π
 
[C18 (mathematical use): representing the first letter of Greek periphereiaperiphery]

pi or pie2 (paɪ)
 
n , pl pies
1.  a jumbled pile of printer's type
2.  a jumbled mixture
 
vb , pies, pies, piing, pied, pies, pieing, pied
3.  to spill and mix (set type) indiscriminately
4.  to mix up
 
[C17: of uncertain origin]
 
pie or pie2
 
n
 
vb
 
[C17: of uncertain origin]

pi3 (paɪ)
 
adj
slang (Brit) pious short for pious

PI
 
abbreviation for
1.  Philippine Islands
2.  private investigator

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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Etymonline
Word Origin & History

pi
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).
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Medical Dictionary

pi (pī)
n. pl. pis

Symbol π The 16th letter of the greek alphabet.

pI (pē'ī')
n.
The pH value for the isoelectric point of a given substance in solution.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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American Heritage
Science Dictionary
pi   (pī)  Pronunciation Key 
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 American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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American Heritage
Cultural Dictionary
pi [(peye)]

The irrational number obtained by dividing the length of the diameter of a circle into its circumference. Pi is approximately 3.1416. The sign for pi is π.

The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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FOLDOC
Computing Dictionary

PI definition


An interface between Prolog application programs and the X Window System that aims to be independent from the Prolog engine, 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)
The Free On-line Dictionary of Computing, © Denis Howe 2010 http://foldoc.org
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American Heritage
Abbreviations & Acronyms
pi
Pali
Pi
inorganic phosphate
PI
  1. performance indicator

  2. politically incorrect

  3. present illness

  4. primary infertility

  5. principal investigator

  6. private investigator

The American Heritage® Abbreviations Dictionary, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Cite This Source
Example sentences for pi
Area enclosed the area enclosed by a circle is the radius squared, multiplied by pi.
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