# pi

^{1}

[ pahy ]

/ paɪ /

### noun, plural pis.

the 16th letter of the Greek alphabet (II, π).

the consonant sound represented by this letter.

Mathematics.

- the letter π, used as the symbol for the ratio of the circumference of a circle to its diameter.
- the ratio itself: 3.141592+.

## RELATED WORDS

sleuth, gumshoe, detective, spy, cop, eavesdropper, agent, tail, investigator, sleuthhound, flatfoot, dick, tracker, bloodhound, snoop, P.I., peeper, eye, inspector, operative

## Nearby words

## Origin of pi

^{1}

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

## Definition for pis (2 of 2)

## pi

^{2}

### or pie

[ pahy ]

/ paɪ /

### noun, plural pies.

printing types mixed together indiscriminately.

any confused mixture; jumble.

### verb (used with object), pied, pi·ing.

to reduce (printing types) to a state of confusion.

to jumble.

## Origin of pi

^{2}

First recorded in 1650–60; origin uncertain

Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

## Examples from the Web for pis

## British Dictionary definitions for pis (1 of 4)

## PI

### abbreviation for

Philippine Islands

private investigator

## British Dictionary definitions for pis (2 of 4)

## pi

^{1}

/ (paɪ) /

### noun plural pis

the 16th letter in the Greek alphabet (Π, π), a consonant, transliterated as p

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

## Word Origin for pi

C18 (mathematical use): representing the first letter of Greek periphereia periphery

## British Dictionary definitions for pis (3 of 4)

## pi

^{2}

### pie

/ (paɪ) /

### noun plural pies

a jumbled pile of printer's type

a jumbled mixture

### verb pies, piing, pied, pies, pieing or pied (tr)

to spill and mix (set type) indiscriminately

to mix up

## Word Origin for pi

C17: of uncertain origin

## British Dictionary definitions for pis (4 of 4)

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

## Word Origin and History for pis

## pi

Greek letter, from Hebrew, literally "little mouth." As the name of the mathematical constant, from 1841 in English, used in Latin 1748 by Swiss mathematician Leonhart Euler (1707-1783), as an abbreviation of Greek periphereia "periphery." For the meaning "printer's term for mixed type," see pie (3).

Online Etymology Dictionary, © 2010 Douglas Harper

## Medicine definitions for pis (1 of 2)

## pi

[ pī ]

### n. pl. pis

The 16th letter of the Greek alphabet.

## Medicine definitions for pis (2 of 2)

## 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.

## Science definitions for pis

## pi

[ 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 American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

## Culture definitions for pis

## 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 New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.