1

pi

play
noun \ˈpī\

Definition of pi

plural

pis

play \ˈpīz\
  1. 1 :  the 16th letter of the Greek alphabet — see alphabet table

  2. 2a :  the symbol π denoting the ratio of the circumference of a circle to its diameterb :  the ratio itself :  a transcendental number having a value rounded to eight decimal places of 3.14159265

Origin and Etymology of pi

Middle Greek, from Greek pei, of Semitic origin; akin to Hebrew pe

Other Alphabet Terms


2

pi

play
noun \ˈpī\
variants: or less commonly

Definition of pi

plural

pies

  1. 1 :  type that is spilled or mixed

  2. 2 :  a pi character or matrix

Origin and Etymology of pi

origin unknown


3

pi

verb
variants: or less commonly

Definition of pi

pied

;

piing

or

pieing

  1. transitive verb
  2. :  to spill or throw (type or type matter) into disorder

  3. intransitive verb
  4. :  to become pied

First Known Use of pi

1889


4

pi

adjective
variants: or less commonly

Definition of pi

  1. 1 :  not intended to appear in final printing pi lines

  2. 2 :  capable of being inserted only by hand pi characters

First Known Use of pi

circa 1940


PI

abbreviation

Definition of PI

  1. 1 Philippine Islands

  2. 2 private investigator

  3. 3 programmed instruction



PI Defined for Kids

pi

play
noun \ˈpī\

Definition of pi for Students

plural

pis

\ˈpīz\
  1. 1 :  the symbol π representing the ratio of the circumference of a circle to its diameter

  2. 2 :  the ratio itself having a value of about 3.1416


Law Dictionary

PI

abbreviation

Legal Definition of PI

  1. private investigator



Seen and Heard

What made you want to look up pi? Please tell us where you read or heard it (including the quote, if possible).

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

WORD OF THE DAY

to plunder or ravage

Get Word of the Day daily email!

Test Your Vocabulary

Time Traveler Quiz: Which Word Came First?

  • time-traveler-quiz-which-word-came-first
  • Which came first?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Syn City

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!