# 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+.

## QUIZZES

#### TAKE THIS QUIZ TO SEE WHAT YOU KNOW ABOUT HIGH SCHOOL PUNCTUATION!

Commas mark divisions in sentences. Periods end declarative sentences. Apostrophes show possession. Easy, right? Well, punctuation can get pretty tricky—fast. Think you got what it takes to be a punctuation expert? Take our quiz to prove it!

Question 1 of 10

Which of the options below is the best punctuation for the sentence? It__s your turn to pick the movie __ but your sister gets to pick the board game we _ re going to play.

Its your turn to pick the movie but your sister gets to pick the board game we’re going to play.

It’s your turn to pick the movie but your sister gets to pick the board game were going to play.

It’s your turn to pick the movie, but your sister gets to pick the board game we’re going to play.

TAKE THE QUIZ TO FIND OUT## Origin of pi

^{1}

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

## Words nearby pi

## 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. 2020

## Example sentences 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

## Medical definitions for pis (1 of 2)

pi

[ pī ]

### n. pl. pis

The 16th letter of the Greek alphabet.

## Medical 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.

## Scientific 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.

## Cultural 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.