pi

¹

[ pahy ]

noun

, plural pis.

1. the 16th letter of the Greek alphabet (Π, π).
2. the consonant sound represented by this letter.
3. Mathematics.
   1. the letter π, used as the symbol for the ratio of the circumference of a circle to its diameter.
   2. the ratio itself: 3.141592+.

pi

²

or pie

[ pahy ]

noun

, plural pies.

1. printing types mixed together indiscriminately.
2. any confused mixture; jumble.

verb (used with object)

, pied, pi·ing.

1. to reduce (printing types) to a state of confusion.
2. to jumble.

PI

³

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

Pi.

⁴

or pi.

abbreviation for

1. piaster.

P.I.

⁵

abbreviation for

1. Philippine Islands.
2. Also PI, p.i. private investigator.

pi

¹

/ paɪ /

noun

1. a jumbled pile of printer's type
2. a jumbled mixture

verb

1. to spill and mix (set type) indiscriminately
2. to mix up

PI

²

abbreviation for

1. Philippine Islands
2. private investigator

pi

³

/ paɪ /

noun

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

pi

⁴

/ paɪ /

adjective

1. slang.
   short for pious pious

pi

/ pī /

1. 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.

pi

1. 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.

Word History and Origins

Origin of pi¹

First recorded in 1835–45; from Greek pî, peî, used in mathematics to represent Greek periphérion periphery ( def )

Origin of pi²

First recorded in 1650–60; origin uncertain

Word History and Origins

Origin of pi¹

C17: of uncertain origin

Origin of pi²

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

Example Sentences

By 1970, with a partnership in a successful PI agency and a stable and happy family, Easy Rawlins is a changed and contented man.

From Los Angeles Times

When Minnie Polson comes to the duo’s PI agency seeking help, things go south after an ill-timed remark causes her to storm out.

From Los Angeles Times

Senior vice president at the PI, Dr Duncan French, acknowledges the UFC has a responsibility, not just to their own roster of between 650-670 fighters, but to those involved at a much lower level.

From BBC

He expects that exciting things will soon also happen in the field of "Explainable AI" at the Lamarr Institute, where he is a PI and Chair of AI in the Life Sciences.

From Science Daily

"Essentially, our synthesis surface becomes a canvas for painting with DNA molecules at the micrometer scale," says Jory Lietard, PI in the Institute of Inorganic Chemistry.

From Science Daily

Related Words

• inquiry agent
• P.I.
• private detective
• private dick
• private eye
• private investigator
• sleuth