Pi (disambiguation)

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

Pi, π or Π may also refer to:

Places

Pi (.hack), a fictional character from the multimedia franchise .hack//G.U.
Pi, a character in both:
- Life of Pi, a 2001 novel, and
- Life of Pi (film), a 2012 adaptation
Pi, a member of Team Robo in Sega Soccer Slam
Pi, a character in the 2006 animated film Shark Bait and the 2012 sequel The Reef 2: High Tide

Pi (instrument), 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
Pi Recordings, a record label

π, a measure of nucleotide diversity
Π or Osmotic pressure
P_i, an inorganic phosphate group
Isoelectric point (pI), the pH at which a particular molecule carries no net electrical charge in the statistical mean
Pi bond, a chemical bond

$Π$ , a glyph representing the product of a sequence of terms
$Π 0 n$ , a set in the arithmetical hierarchy
$Π 1 n$ , a set in the analytical hierarchy
$Π P i$ , a set in the polynomial hierarchy
$Π(x)$ (Pi function), the Gamma function when offset to coincide with the factorial
$Π(n, k)$ , the complete elliptic integral of the third kind
$π n (X)$ , the $n$ th homotopy group of $X$
$π$ -calculus, a process calculus
Prime-counting function or $π (x)$
$\pi$ , the population proportion in statistics

Pi (prefix symbol), the prefix symbol of the binary unit prefix pebi
Π, for plaintiff, in legal shorthand
Π, stands for Pierikos F.C. kit logo
Linotype machine#Pi matrices or pi characters, uncommon characters used in typesetting
Pi font, a term for some kinds of dingbat fonts
Pali (ISO 639-1 language code "pi")
Pi Day, an annual celebration of March 14 (3/14)'s relationship with the mathematical constant
Principal investigator, holder of an independent grant