Pi (disambiguation)

Pi, or π is the mathematical constant equal to a circle's circumference divided by its diameter.

Pi or PI may also refer to:

Letter Pi (π)

• Pi (letter), the Greek letter
• Lowercase π:
  • π(x) (pi function), the prime-counting function
  • π_n(X) the nth homotopy group of X
  • Pi bond
  • Parallax in astrometry, especially annual parallax.
  • A song from the Kate Bush album Aerial
  • Shorthand for pion
  • A men's fragrance from Givenchy
  • The symbol for political life used in Boethius' Consolation of Philosophy
  • Pi-calculus, a process calculus.
• Uppercase Π:
  • Osmotic pressure
  • The product symbol
  • Π(x) (Pi function), the Gamma function when offset to coincide with the factorial
    • π(x), the reciprocal of the Pi reciprocal
  • $\Pi^0_n$, a set in the Arithmetical hierarchy
  • $\Pi^1_n$, a set in the Analytical hierarchy
  • $\Pi^P_i$, a set in the Polynomial hierarchy

Pi as a word

• Pi (instrument)
• Pi (.hack), a fictional character from the multimedia franchise .hack//G.U.
• Pi Magazine
• Pi Recordings, a record label
• Pi, Catalonia, a town in Catalonia, Spain
• Pi County in Sichuan, China
• Pi (film), a 1998 film directed by Darren Aronofsky
• Pi Studios, a video game developer
• Pi (state) a vassal state in Zhou Dynasty China (1046–256 BCE)
• "Pi", a song from the Hard 'n Phirm album Horses and Grasses
• Pi, a member of Team Robo in Sega Soccer Slam
• Pi, a fictional character in the novel Life of Pi
• 皮 (hanyu pinyin : Pí), a Chinese character meaning skin, bark

PI as an abbreviation

Science

• Parental Investment in biology
• Primary immunodeficiency
• An inorganic phosphate group (as P_i)
• The isoelectric point (as pI)
• Phosphatidylinositol
• Propidium iodide
• Polyimide
• Ponderal Index
• Potential instability in meteorology
• Protease inhibitor (pharmacology), class of drugs used to treat or prevent infection by viruses, including HIV and Hepatitis C
• Protease inhibitor (biology), molecules that inhibit the function of proteases
• Pistillata a gene that influences the development of flowers in the ABC Model of Flower Development
• Prediction interval in statistics
• Paternity Index

Companies and organizations

• Parents for Inclusion
• Perimeter Institute for Theoretical Physics
• Privacy International
• Pasteur Institute
• Sun Air (Fiji) (IATA airline code: PI)

Professional occupations

• Photographic interpreter, an aerospace and strategic reconnaissance term
• In legal shorthand, it refers to a plaintiff
• Personal injury attorney
• Principal investigator, the lead scientist in a project
• Private investigator
• Permanent injunction

Computing

• Page impressions, an online advertising term
• Pebi, a Binary prefix
• Programmed instruction
• Provider Independent Address Space
• Processing Instruction, SGML and XML node type
• Raspberry Pi, a miniature motherboard

Other

• Pass interference in American football
• Parameter indicator, in ISO standards
• People's Initiative
• Profitability index
• Personal injury
• The Philippines (from "Philippine Islands")
• PI controller, a concept in automation and control engineering
• Piauí, a state in Brazil
• Poison Idea, American hardcore punk band
• Public intoxication
• Seattle Post-Intelligencer
• Philippine Idol
• Primitive Instinct
• Proforma invoice
• Plasticity index
• Prison Industry, as often coined on the Fox hit series Prison Break
• Marine Corps Recruit Depot Parris Island
• Philippine Islands
• Partit per la Independència, a short lived political party in Catalonia of the 1990s

See also

• PI System data analysis software, made by OSIsoft
• P
• Pi Islands
• Pie (disambiguation)

This disambiguation page lists articles associated with the same title. If an internal link led you here, you may wish to change the link to point directly to the intended article.