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, the symbol for maxterm notation in Karnaugh mapping
Raspberry Pi, a single-board computer developed by Raspberry Pi Foundation; also known as Pi

$Π$ , 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_n(X), the fundamental n-groupoid of X
- $Π(X)$ , the fundamental groupoid of $X$
$π n (X)$ , the $n$ th cohomotopy set of $X$
$π n$ , a notation for the scalar projection onto the n-th component
$π$ -calculus, a process calculus
Prime-counting function or $π (x)$
$\pi$ , the population proportion in statistics

Language and typography

Places