Letter Pi (π)

• Pi (letter)
  Pi (letter)
  Pi is the sixteenth letter of the Greek alphabet, representing . In the system of Greek numerals it has a value of 80. Letters that arose from pi include Cyrillic Pe , Coptic pi , and Gothic pairthra .The upper-case letter Π is used as a symbol for:...
  
  , the Greek letter
• Lowercase π:
  • (pi function), the prime-counting function
  • the th homotopy group
    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, which records information about loops in a space...
    
     of
  • Pi bond
    Pi bond
    In chemistry, pi bonds are covalent chemical bonds where two lobes of one involved atomic orbital overlap two lobes of the other involved atomic orbital...
    
    
  • Parallax
    Parallax
    Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines. The term is derived from the Greek παράλλαξις , meaning "alteration"...
    
     in astrometry
    Astrometry
    Astrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. The information obtained by astrometric measurements provides information on the kinematics and physical origin of our Solar System and our Galaxy, the Milky...
    
    , especially annual parallax.
  • A song from the Kate Bush album Aerial
    Aerial (album)
    Aerial is the eighth studio album by British singer-songwriter and musician Kate Bush.-Overview:Aerial is Bush's first double album, and was released after a twelve year absence from the music industry during which Bush devoted her time to family and the rearing of her son, Bertie...
    
    
  • Shorthand for pion
    Pion
    In particle physics, a pion is any of three subatomic particles: , , and . Pions are the lightest mesons and they play an important role in explaining the low-energy properties of the strong nuclear force....
    
    
  • A men's fragrance from Givenchy
    Givenchy
    Givenchy is a French brand of clothing, accessories, perfumes and cosmetics with Parfums Givenchy.The house of Givenchy was founded in 1952 by designer Hubert de Givenchy and is a member of Chambre Syndicale de la Haute Couture et du Pret-a-Porter...
    
    
  • The symbol for political life used in Boethius' Consolation of Philosophy
    Consolation of Philosophy
    Consolation of Philosophy is a philosophical work by Boethius, written around the year 524. It has been described as the single most important and influential work in the West on Medieval and early Renaissance Christianity, and is also the last great Western work that can be called Classical.-...
    
    
  • Pi-calculus
    Pi-calculus
    In theoretical computer science, the π-calculus is a process calculus originally developed by Robin Milner, and David Walker as a continuation of work on the process calculus CCS...
    
    , a process calculus
    Process calculus
    In computer science, the process calculi are a diverse family of related approaches for formally modelling concurrent systems. Process calculi provide a tool for the high-level description of interactions, communications, and synchronizations between a collection of independent agents or processes...
    
    .
• Uppercase Π:
  • Osmotic pressure
    Osmotic pressure
    Osmotic pressure is the pressure which needs to be applied to a solution to prevent the inward flow of water across a semipermeable membrane....
    
    
  • The product symbol
  • (Pi function), the Gamma function
    Gamma function
    In mathematics, the gamma function is an extension of the factorial function, with its argument shifted down by 1, to real and complex numbers...
    
     when offset to coincide with the factorial
    • , the reciprocal of the Pi reciprocal
  • , a set in the Arithmetical hierarchy
    Arithmetical hierarchy
    In mathematical logic, the arithmetical hierarchy, arithmetic hierarchy or Kleene-Mostowski hierarchy classifies certain sets based on the complexity of formulas that define them...
    
    
  • , a set in the Analytical hierarchy
    Analytical hierarchy
    In mathematical logic and descriptive set theory, the analytical hierarchy is a higher type analogue of the arithmetical hierarchy. It thus continues the classification of sets by the formulas that define them.-The analytical hierarchy of formulas:...
    
    
  • , a set in the Polynomial hierarchy
    Polynomial hierarchy
    In computational complexity theory, the polynomial hierarchy is a hierarchy of complexity classes that generalize the classes P, NP and co-NP to oracle machines...
    
    

Pi as a word

• Pi (instrument)
  Pi (instrument)
  Pi is the generic term for any of a variety of quadruple reed oboes used in the traditional music of Thailand. It is very similar in construction and playing technique to the Cambodian sralai.-Varieties:*Pi chawa *Pi klang...
  
  
• Pi (.hack), a fictional character from the multimedia franchise .hack//G.U.
• Pi Magazine
  Pi Magazine
  Pi is the name of the official student publications of the University College London Union.-History:Pi was originally launched as a newspaper. In the aftermath of World War II, there was strong popular support amongst college and UCL Union officials for some sort of community project that would...
  
  
• Pi Recordings
  Pi Recordings
  Pi Recordings is a jazz record label whose motto is "dedicated to the innovative". Pi was founded in 2001 by Seth Rosner. He was joined as partner by Yulun Wang in 2002.- Discography :*Pi 01: Everybodys Mouth's a Book - Henry Threadgill...
  
  , a record label
• Pi, Catalonia, a town in Catalonia, Spain
• Pi County
  Pi County
  Pi County is a county within Chengdu City, Sichuan Province, China. It is located just 10 km north-west of Chengdu's city centre...
  
   in Sichuan, China
• Pi (film)
  Pi (film)
  Pi, also titled ,WorldCat gives the title as [Pi] and provides a note which states, "Title is the mathematical symbol for Pi." . Amazon gives the title as Pi with no notation concerning the math symbol . is a 1998 American psychological thriller film written and directed by Darren Aronofsky...
  
  , a 1998 film directed by Darren Aronofsky
• Pi Studios
  Pi Studios
  Pi Studios is 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...
  
  , a video game developer
• Pi (state)
  Pi (state)
  The State of Pī was a Zhou Dynasty vassal state during the Spring and Autumn Period of Chinese history. Also known as the State of Xue , Pi was ruled by members of the Ren family...
  
   a vassal state in Zhou Dynasty China (1046–256 BCE)
• "Pi", a song from the Hard 'n Phirm album Horses and Grasses
  Horses and Grasses
  Horses and Grasses is the first album of the comedy band Hard 'n Phirm. It was released in 2005 to acclaim, especially for the fourth track "Pi" and for their bluegrass Radiohead medley titled "Rodeohead".-Track listing:# The Carbon Cycle – 2:19...
  
  
• Pi, a member of Team Robo in Sega Soccer Slam
  Sega Soccer Slam
  Sega Soccer Slam is a sports game released for the PlayStation 2, Xbox, and GameCube in the year 2002.-Gameplay:Sega Soccer Slam is much different than standard traditional real-life sports games because of its exaggerated interpretation of soccer and allowing characters to punch one another and...
  
  
• Pi, a fictional character in the novel Life of Pi
  Life of Pi
  Life of Pi is a fantasy adventure novel by Yann Martel published in 2001. The protagonist, Piscine Molitor "Pi" Patel, an Indian boy from Pondicherry, explores issues of spirituality and practicality from an early age...
  
  
• 皮 (hanyu pinyin : Pí), a Chinese character meaning skin, bark

Science

• Parental Investment
  Parental investment
  In evolutionary biology, parental investment is any parental expenditure that benefits one offspring at a cost to parents' ability to invest in other components of fitness...
  
   in biology
• Primary immunodeficiency
  Primary immunodeficiency
  Primary immunodeficiencies are disorders in which part of the body's immune system is missing or does not function properly. To be considered a primary immunodeficiency, the cause of the immune deficiency must not be secondary in nature...
  
  
• An inorganic phosphate
  Phosphate
  A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
  
   group (as P_i)
• The isoelectric point
  Isoelectric point
  The isoelectric point , sometimes abbreviated to IEP, is the pH at which a particular molecule or surface carries no net electrical charge....
  
   (as pI)
• Phosphatidylinositol
  Phosphatidylinositol
  Phosphatidylinositol is a negatively charged phospholipid and a minor component in the cytosolic side of eukaryotic cell membranes....
  
  
• Propidium iodide
  Propidium iodide
  Propidium iodide is an intercalating agent and a fluorescent molecule with a molecular mass of 668.4 Da that can be used to stain cells. When excited with 488 nm wavelength light, it fluoresces red...
  
  
• Polyimide
  Polyimide
  Polyimide is a polymer of imide monomers. The structure of imide is as shown. Polyimides have been in mass production since 1955...
  
  
• Ponderal Index
  Ponderal index
  The Ponderal Index is a measure of leanness of a person calculated as a relationship between mass and height.It was first proposed 1921 as "Corpulence Index" by Rohrer...
  
  
• Potential instability in meteorology
• Protease inhibitor (pharmacology)
  Protease inhibitor (pharmacology)
  Protease inhibitors are a class of drugs used to treat or prevent infection by viruses, including HIV and Hepatitis C. PIs prevent viral replication by inhibiting the activity of proteases, e.g.HIV-1 protease, enzymes used by the viruses to cleave nascent proteins for final assembly of new...
  
  , class of drugs used to treat or prevent infection by viruses, including HIV and Hepatitis C
• Protease inhibitor (biology)
  Protease inhibitor (biology)
  In biology and biochemistry, protease inhibitors are molecules that inhibit the function of proteases. Many naturally occurring protease inhibitors are proteins....
  
  , molecules that inhibit the function of proteases
• Pistillata a gene that influences the development of flowers in the ABC Model of Flower Development
  The ABC Model of Flower Development
  The ABC model of flower development in angiosperms was formulated by Enrico Coen and Elliot Meyerowitz in 1991. This model is built on the observation of mutants with defects in floral organ development...
  
  
• Prediction interval
  Prediction interval
  In statistical inference, specifically predictive inference, a prediction interval is an estimate of an interval in which future observations will fall, with a certain probability, given what has already been observed...
  
   in statistics
• Paternity Index
  Paternity Index
  In Paternity testing,Paternity Index is a calculated value generated for a single genetic marker or locus and is associated with the statistical strength or weight of that locus in favor of or against parentage given the phenotypes of the tested participants and the inheritance scenario...
  
  

Companies and organizations

• Parents for Inclusion
  Parents for Inclusion
  Parents for Inclusion is a registered charity in the United Kingdom which aims to help parents of children with special educational needs and physical disabilities. The charity is pro-inclusion and was founded in 1984 as Parents in Partnership....
  
  
• Perimeter Institute for Theoretical Physics
  Perimeter Institute for Theoretical Physics
  Perimeter Institute for Theoretical Physics is an independent, resident-based research institute devoted to foundational issues in theoretical physics located in Waterloo, Ontario, Canada. Perimeter Institute was founded in 1999 by Mike Lazaridis...
  
  
• Privacy International
  Privacy International
  Privacy International is a UK-based non-profit organisation formed in 1990, "as a watchdog on surveillance and privacy invasions by governments and corporations." PI has organised campaigns and initiatives in more than fifty countries and is based in London, UK.-Formation, background and...
  
  
• Pasteur Institute
  Pasteur Institute
  The Pasteur Institute is a French non-profit private foundation dedicated to the study of biology, micro-organisms, diseases, and vaccines. It is named after Louis Pasteur, who made some of the greatest breakthroughs in modern medicine at the time, including pasteurization and vaccines for anthrax...
  
  
• Sun Air (Fiji)
  Sun Air (Fiji)
  Fiji Airlines Limited, trading as Pacific Sun is an airline headquartered at Nadi International Airport in Nadi, Fiji. It operates scheduled services to twelve destinations within the Fijian Islands as well as regionally within the Pacific Islands...
  
   (IATA airline code: PI)

Professional occupations

• Photographic interpreter, an aerospace
  Aerospace
  Aerospace comprises the atmosphere of Earth and surrounding space. Typically the term is used to refer to the industry that researches, designs, manufactures, operates, and maintains vehicles moving through air and space...
  
   and strategic reconnaissance term
• In legal shorthand, it refers to a plaintiff
• Personal injury
  Personal injury
  Personal injury is a legal term for an injury to the body, mind or emotions, as opposed to an injury to property. The term is most commonly used to refer to a type of tort lawsuit alleging that the plaintiff's injury has been caused by the negligence of another, but also arises in defamation...
  
   attorney
• Principal investigator
  Principal investigator
  A principal investigator is the lead scientist or engineer for a particular well-defined science project, such as a laboratory study or clinical trial....
  
  , the lead scientist in a project
• Private investigator
  Private investigator
  A private investigator , private detective or inquiry agent, is a person who can be hired by individuals or groups to undertake investigatory law services. Private detectives/investigators often work for attorneys in civil cases. Many work for insurance companies to investigate suspicious claims...
  
  
• Permanent injunction
  Injunction
  An injunction is an equitable remedy in the form of a court order that requires a party to do or refrain from doing certain acts. A party that fails to comply with an injunction faces criminal or civil penalties and may have to pay damages or accept sanctions...
  
  

Computing

• Page impressions, an online advertising
  Online advertising
  Online advertising is a form of promotion that uses the Internet and World Wide Web to deliver marketing messages to attract customers. Examples of online advertising include contextual ads on search engine results pages, banner ads, blogs, Rich Media Ads, Social network advertising, interstitial...
  
   term
• Pebi, a Binary prefix
  Binary prefix
  In computing, a binary prefix is a specifier or mnemonic that is prepended to the units of digital information, the bit and the byte, to indicate multiplication by a power of 2...
  
  
• Programmed instruction
  Programmed instruction
  Programmed instruction is the name of the technology invented by the behaviorist B.F. Skinner to improve teaching. It is based on his theory of verbal behavior as a means to accelerate and increase conventional educational learning.-Programmed instruction:...
  
  
• Provider Independent Address Space
  Provider Independent Address Space
  A provider-independent address space is a block of IP addresses assigned by a regional Internet registry directly to an end-user organization...
  
  
• Processing Instruction
  Processing Instruction
  A Processing Instruction is an SGML and XML node type, which may occur anywhere in the document, intended to carry instructions to the application....
  
  , SGML and XML node type
• Raspberry Pi
  Raspberry Pi
  The Raspberry Pi is a single-board computer developed by the Raspberry Pi Foundation. Scheduled for public release in December 2011, the foundation plans to release two versions that range from US$25 to $35...
  
  , a miniature motherboard

Other

• Pass interference
  Pass interference
  In American and Canadian gridiron football, pass interference is a penalty that occurs when a player interferes with an eligible receiver's ability to make a fair attempt to catch a forward pass. Pass interference may include tripping, pushing, pulling, or cutting in front of the receiver or...
  
   in American football
• Parameter indicator, in ISO
  International Organization for Standardization
  The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...
  
   standards
• People's Initiative
  People's Initiative
  People’s Initiative or "PI" is one of the modes in which the 1987 Constitution of the Philippines could be amended. The other two modes are via Constituent Assembly or "Con-Ass" and Constitutional Convention or "Con-Con"; which also allow revisions....
  
  
• Profitability index
  Profitability index
  Profitability index , also known as profit investment ratio and value investment ratio , is the ratio of payoff to investment of a proposed project...
  
  
• Personal injury
  Personal injury
  Personal injury is a legal term for an injury to the body, mind or emotions, as opposed to an injury to property. The term is most commonly used to refer to a type of tort lawsuit alleging that the plaintiff's injury has been caused by the negligence of another, but also arises in defamation...
  
  
• The Philippines
  Philippines
  The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
  
   (from "Philippine Islands")
• PI controller, a concept in automation and control engineering
• Piauí
  Piauí
  Piauí is one of the states of Brazil, located in the northeastern part of the country.Piauí has the shortest coastline of any of the non-landlocked Brazilian states at 66 km , and the capital, Teresina, is the only state capital in the north east to be located inland...
  
  , a state in Brazil
• Poison Idea
  Poison Idea
  Poison Idea was an American hardcore punk band formed in Portland, Oregon in 1980. The band originally dissolved in 1993, but has been playing intermittently since 1998.-Formation, 1980's and 90's:...
  
  , American hardcore punk band
• Public intoxication
  Public intoxication
  Public intoxication, also known as "drunk and disorderly", is a summary offense in many countries rated to public cases or displays of drunkenness...
  
  
• Seattle Post-Intelligencer
  Seattle Post-Intelligencer
  The Seattle Post-Intelligencer is an online newspaper and former print newspaper covering Seattle, Washington, United States, and the surrounding metropolitan area...
  
  
• Philippine Idol
  Philippine Idol
  Philippine Idol was the first franchise of Idol series in the Philippines, the 35th country in the world to air a national Idol franchise and the sixth in Asia. The franchise was first awarded by FremantleMedia, 19 Entertainment and CKX, Inc. to Associated Broadcasting Company in 2006 and then to...
  
  
• Primitive Instinct
  Primitive Instinct
  Primitive Instinct are a Progressive/Classic Rock band, formed in 1987 in Maidstone, Kent, England, by guitarist/vocalist/songwriter Nick Sheridan, who still fronts the band today. To the uninitiated, a ballpark description of PI would be modern-day Marillion meets Pink Floyd...
  
  
• Proforma invoice
  Invoice
  An invoice or bill is a commercial document issued by a seller to the buyer, indicating the products, quantities, and agreed prices for products or services the seller has provided the buyer. An invoice indicates the buyer must pay the seller, according to the payment terms...
  
  
• Plasticity index
• Prison Industry, as often coined on the Fox hit series Prison Break
  Prison Break
  Prison Break is an American television serial drama created by Paul Scheuring, that was broadcast on the Fox Broadcasting Company for four seasons, from 2005 until 2009. The series revolves around two brothers; one has been sentenced to death for a crime he did not commit, and the other devises an...
  
  
• Marine Corps Recruit Depot Parris Island
  Marine Corps Recruit Depot Parris Island
  Marine Corps Recruit Depot Parris Island is an military installation located within Port Royal, South Carolina, approximately south of Beaufort, the community that is typically associated with the installation. MCRD Parris Island is used for the training of enlisted Marines...
  
  
• Philippine Islands
• Partit per la Independència
  Partit per la Independència
  Partit per la Independència was a short lived political party in Catalonia of the 1990s that campaigned for independence for Catalonia from Spain. It was created by Àngel Colom and Pilar Rahola in 1996 as a schism from Republican Left of Catalonia, another independentist party...
  
  , a short lived political party in Catalonia of the 1990s

See also

• PI System
  Pi system
  In mathematics, a π-system on a set Ω is a set P, consisting of certain subsets of Ω, such that* P is non-empty.* A ∩ B ∈ P whenever A and B are in P....
  
   data analysis software, made by OSIsoft
  OSIsoft
  OSIsoft, LLC is a worldwide manufacturer of Application software for real-time data infrastructure solutions, called the PI System. Founded in 1980, OSIsoft, LLC is privately held and headquartered in San Leandro, CA, with operations worldwide....
  
  
• P
  P
  P is the sixteenth letter of the basic modern Latin alphabet.-Usage:In English and most other European languages, P is a voiceless bilabial plosive. Both initial and final Ps can be combined with many other discrete consonants in English words...
  
  
• Pi Islands
  Pi Islands
  Pi Islands are two islands and several rocks which lie 1 nautical mile 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 1946 Argentine government chart...
  
  
• Pie (disambiguation)
  Pie (disambiguation)
  A pie is a baked food, with a shell usually made of pastry that covers or completely contains a sweet or savory filling.Pie can also refer to:*Pieing, to throw a pie at someone*Pie chart, a type of circular chart...