Pi or is a mathematical constant equal to a circle's circumference divided by its diameter. Pi, π or Π may also refer to:

Language and typography

Pi (letter) Pi (uppercase Π, lowercase π and ϖ; el, πι ) is the sixteenth letter of the Greek alphabet, representing the voiceless bilabial plosive . In the system of Greek numerals it has a value of 80. It was derived from the Phoenician letter Pe ...

, in the Greek alphabet * Pi characters, uncommon characters in typesetting * Pi font, a term for some kinds of

dingbat In typography, a dingbat (sometimes more formally known as a printer's ornament or printer's character) is an ornament, specifically, a glyph used in typesetting, often employed to create box frames, (similar to box-drawing characters) or a ...

fonts *

Pali Pali () is a Middle Indo-Aryan liturgical language native to the Indian subcontinent. It is widely studied because it is the language of the Buddhist ''Pāli Canon'' or ''Tipiṭaka'' as well as the sacred language of ''Theravāda'' Buddhism ...

, an Indo-Aryan language (ISO 639-1 code: pi)

Places

Pi (state) Pi () was a Zhou dynasty (1045–256 BC) vassal state in ancient China. Also known as Xue (), Pi was ruled by members of the ''Ren'' (任) family. Its progenitor Xi Zhong (奚仲), had been the Minister of Chariots (车正) for Yu the Great during ...

, an ancient state during China's Zhou dynasty * Pi, Catalonia, an integrated village of Bellver de Cerdanya, Catalonia, Spain *

Pi County Pidu District formerly known as Pi County or Pixian is one of 11 urban districts of the prefecture-level city of Chengdu, the capital of Sichuan Province, Southwest China. It was approved from the former Pi County by the State Council on Novembe ...

, Sichuan province, China *

Pi Islands Pi Islands are two islands and several rocks which lie east of the northeast end of Omega Island among the Melchior Islands, Palmer Archipelago. The name, derived from the 16th letter of the Greek alphabet, appears to have been first used on a 1 ...

, Palmer Archipelago, Antarctica *

Philippine Islands The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

, another name for the Philippines

People

Given name

Pi de Bruijn Pi de Bruijn (born 28 August 1942) is a Dutch architect from Losser, Overijssel, the Netherlands . He is a design principal at the Office de Architecten Cie., located in Amsterdam. History Bruijn graduated from the Delft University of Technology ...

(born 1942), Dutch architect *

Pi O П. O. (or Pi O, born 1951) is a Greek-Australian, working class, anarchist poet. Born in Katerini, Greece, П. O. came to Australia with his family around 1954. After time in Bonegilla Migrant Reception and Training Centre, the family moved to t ...

or П. O. (born 1951), Greek-Australian anarchist poet * Pi Schwert (1892–1941), American baseball player and politician * Pi Vèriss, Dutch songwriter and composer

Surname

Bi (surname) Bi () is a Chinese surname. It is listed 76th in the Song dynasty classic text, the ''Hundred Family Surnames''.K. S. Tom. 989(1989). Echoes from Old China: Life, Legends and Lore of the Middle Kingdom. University of Hawaii Press. . Notable peop ...

(), romanized as Pi in Wade–Giles *

Pi (surname) Pi is the Mandarin pinyin romanization of the Chinese surname written in Chinese character. It is romanized P'i in Wade–Giles, and Pei in Cantonese. Pi is listed 85th in the Song dynasty classic text ''Hundred Family Surnames''. According to ...

(), a Chinese surname * Enric Pi (born 1983), Catalan footballer *

Francesc Pi i Margall Francesc Pi i Margall (Spanish: Francisco Pi y Margall) (29 April 1824 – 29 November 1901) was a Spanish federalist and republican politician and theorist who served as president of the short-lived First Spanish Republic in 1873. He was al ...

(1824–1901), Catalan politician *

Jordi Sabater Pi Jordi Sabater Pi (2 August 1922 – 5 August 2009) was a Spanish-Catalan primatologist and worldwide specialist in ethology, the study of animal behavior. Sabater was known for describing the cultural behaviors of several species, including the ...

(1922–2009), Catalan primatologist and ethologist *

Meritxell Mateu i Pi Meritxell Mateu i Pi (born January 19, 1966) is an Andorran politician, member of the Partit Liberal d'Andorra who served as Minister of Foreign Affairs from 2007 to 2009, being the first female to hold this office. Previous positions she has h ...

(born 1966), Andorran diplomat *

Ot Pi Ot Pi is a Spanish bike-trials rider, often regarded as the man responsible for the discipline's origin. He has won several world titles and is featured on a number of videos that showcase the sport. Ot Pi (aka "Hot Pie") Isern made his U.S. debu ...

(born 1970), Catalan mountain bike trials rider *

Pedro Pi Pedro Pi (14 September 1899 – 3 January 1970) was a sailor from Spain, who represented his country at the Sailing at the 1924 Summer Olympics – 6 Metre, 1924 Summer Olympics in Le Havre, France. References Sources

* * 1899 births ...

(1899–1970), Spanish sailor *

Renzo Pi Hugarte Renzo Wifredo Pi Hugarte (Durazno, 23 November 1934 – Montevideo, 15 August 2012) was a Uruguayan scholar, anthropologist, professor, historian and writer. Together with Daniel Vidart he is considered one of the "founding fathers" of anthropolog ...

(1934–2012), Uruguayan anthropologist

Arts, entertainment, and media

Fictional characters

* Pi (.hack), a fictional character from the multimedia franchise ''.hack//G.U.'' * Pi, a character in both: ** ''

Life of Pi ''Life of Pi'' is a Canadian philosophical novel by Yann Martel published in 2001. The protagonist is Piscine Molitor "Pi" Patel, an Indian boy from Pondicherry, India who explores issues of spirituality and metaphysics from an early age. He s ...

'', a 2001 novel, and ** ''Life of Pi'' (film), a 2012 adaptation * Pi, a member of Team Robo in ''

Sega Soccer Slam ''Sega Soccer Slam'', also known as simply ''Soccer Slam'', is a sports game released for GameCube, Xbox, and PlayStation 2 in 2002. Gameplay ''Sega Soccer Slam'' is different from traditional sports games in its exaggerated interpretation of ...

'' * Pi, a character in the 2006 animated film '' Shark Bait'' and the 2012 sequel ''The Reef 2: High Tide''

Music

Pi (instrument) ''Pi'' ( th, ปี่, ) is the generic term for any of a variety of quadruple reed oboes used in the traditional music of Thailand, ''piphat''. It is very similar in construction and playing technique to Burmese Hne and Cambodian ''sralai''. V ...

, a generic term for a variety of double- or quadruple-reed oboes and a free-reed pipe of traditional Thai music * "π", a song by Kate Bush from '' Aerial'' * "Pi", a song by Hard 'n Phirm from ''

Horses and Grasses ''Horses and Grasses'' is the first and only studio album by the comedy band Hard 'n Phirm, released in 2005. Track listing # The Carbon Cycle – 2:19 # American Dinosaurs – 3:32 # An Intro – 0:35 # Pi – 3:14 # Ready – 0:22 # She Na ...

'' *

Pi Recordings Pi Recordings is a jazz record label founded by Seth Rosner in 2001. He was soon joined as partner by Yulun Wang. Pi specializes in avant-garde jazz. Its first two albums were by Henry Threadgill. Pi's roster includes Amir ElSaffar, Anthony Braxt ...

, a record label

Other arts, entertainment, and media

* ''Pi'' (film), a 1998 film directed by Darren Aronofsky * ''P.I.'' (TV series), 2017 Singaporean TV series * ''

Pi magazine ''UCL Pi Media'' is the oldest and largest student journalism society at University College London Union. Initially launched as a newspaper in 1946 and named after former Provost David Pye, it now publishes on three platforms: ''Pi Online'', ''P ...

'', a student publication of the University College London Union *

Pi Studios Pi Studios was a computer game software developer founded in 2002 by Robert Erwin, John Faulkenbury, Rob Heironimus, Dan Kramer and Peter Mack whose first commercial work can be found in Activision's '' Call of Duty: United Offensive''. The co ...

, a video game developer

Science and mathematics

Chemistry and biochemistry

* π, a measure of

nucleotide diversity Nucleotide diversity is a concept in molecular genetics which is used to measure the degree of polymorphism within a population. One commonly used measure of nucleotide diversity was first introduced by Nei and Li in 1979. This measure is defin ...

* Π or

Osmotic pressure Osmotic pressure is the minimum pressure which needs to be applied to a solution to prevent the inward flow of its pure solvent across a semipermeable membrane. It is also defined as the measure of the tendency of a solution to take in a pure ...

* P_i, an inorganic

phosphate In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phospho ...

group *

Isoelectric point The isoelectric point (pI, pH(I), IEP), is the pH at which a molecule carries no net electrical charge or is electrically neutral in the statistical mean. The standard nomenclature to represent the isoelectric point is pH(I). However, pI is also u ...

(pI), the pH at which a particular molecule carries no net electrical charge in the statistical mean *

Pi bond In chemistry, pi bonds (π bonds) are covalent chemical bonds, in each of which two lobes of an orbital on one atom overlap with two lobes of an orbital on another atom, and in which this overlap occurs laterally. Each of these atomic orbitals ...

, a chemical bond

Logic and computer science

* Π, the symbol for maxterm notation in

Karnaugh mapping The Karnaugh map (KM or K-map) is a method of simplifying Boolean algebra expressions. Maurice Karnaugh introduced it in 1953 as a refinement of Edward W. Veitch's 1952 Veitch chart, which was a rediscovery of Allan Marquand's 1881 ''logica ...

Raspberry Pi Raspberry Pi () is a series of small single-board computers (SBCs) developed in the United Kingdom by the Raspberry Pi Foundation in association with Broadcom. The Raspberry Pi project originally leaned towards the promotion of teaching basic ...

, a single-board computer

Mathematics

* , a glyph representing the product of a sequence of terms * , a set in the

arithmetical hierarchy In mathematical logic, the arithmetical hierarchy, arithmetic hierarchy or Kleene–Mostowski hierarchy (after mathematicians Stephen Cole Kleene and Andrzej Mostowski) classifies certain sets based on the complexity of formulas that define th ...

* , a set in the

analytical hierarchy In mathematical logic and descriptive set theory, the analytical hierarchy is an extension of the arithmetical hierarchy. The analytical hierarchy of formulas includes formulas in the language of second-order arithmetic, which can have quantifiers ...

* , a set in the

polynomial hierarchy In computational complexity theory, the polynomial hierarchy (sometimes called the polynomial-time hierarchy) is a hierarchy of complexity classes that generalize the classes NP and co-NP. Each class in the hierarchy is contained within PSPACE. T ...

* (Pi function), the

Gamma function In mathematics, the gamma function (represented by , the capital letter gamma from the Greek alphabet) is one commonly used extension of the factorial function to complex numbers. The gamma function is defined for all complex numbers except ...

when offset to coincide with the factorial * , the complete elliptic integral of the third kind * , the th

homotopy group In mathematics, homotopy groups are used in algebraic topology to classify topological spaces. The first and simplest homotopy group is the fundamental group, denoted \pi_1(X), which records information about loops in a space. Intuitively, homotop ...

of * -calculus, a process calculus *

Prime-counting function In mathematics, the prime-counting function is the function counting the number of prime numbers less than or equal to some real number ''x''. It is denoted by (''x'') (unrelated to the number ). History Of great interest in number theory is t ...

or *

\pi

, the

population proportion In statistics, a population proportion, generally denoted by P or the Greek letter \pi, is a parameter that describes a percentage value associated with a population. For example, the 2010 United States Census showed that 83.7% of the American po ...

in statistics

Physics

Pion In particle physics, a pion (or a pi meson, denoted with the Greek letter pi: ) is any of three subatomic particles: , , and . Each pion consists of a quark and an antiquark and is therefore a meson. Pions are the lightest mesons and, more gene ...

or π, a subatomic particle

Other uses

* Pi (prefix symbol), the prefix symbol of the binary unit prefix pebi * Π, for plaintiff, in

legal shorthand This is a list of abbreviations used in law and legal documents. It is common practice in legal documents to cite other publications by using standard abbreviations for the title of each source. Abbreviations may also be found for common words o ...

* Π, stands for

Pierikos F.C. S.F.K. Pierikos ( el, Σ.Φ.Κ. Πιερικός) is a Greek football club based in Katerini, Greece, part of the major multi-sport club of the same name. Their name was inspired from the State's name of Pieria. The club recently competed in ...

kit logo *

Pi Day Pi Day is an annual celebration of the mathematical constant (pi). Pi Day is observed on March 14 (3/14 in the ''month/day'' format) since 3, 1, and 4 are the first three significant figures of . It was founded in 1988 by Larry Shaw, an e ...

, an annual celebration of March 14 (3/14)'s relationship with the mathematical constant *

Principal investigator In many countries, the term principal investigator (PI) refers to the holder of an independent grant and the lead researcher for the grant project, usually in the sciences, such as a laboratory study or a clinical trial. The phrase is also often us ...

, holder of an independent grant *

Private investigator A private investigator (often abbreviated to PI and informally called a private eye), a private detective, or inquiry agent is a person who can be hired by individuals or groups to undertake investigatory law services. Private investigators of ...