Phi (disambiguation)
# Phi (disambiguation)

Phi (uppercase Φ, lowercase φ, or maths symbol ϕ) is the 21st letter of the Greek alphabet.

Phi or PHI may also refer to:

## Science and technology

### Mathematics

* Golden ratio (φ)
* Phi coefficient, a measure of association for two binary variables introduced by Karl Pearson
* Euler's totient function or phi function
* Integrated information theory (IIT) the symbol of which is φ is a mathematical theory of consciousness developed under the lead of the neuroscientist Giulio Tononi
* Standard normal distribution, $\Phi (x)$ notating its cumulative distribution function and $\phi (x)$ its probability density function

### Physics, chemistry and biology

* Phi meson, in particle physics
* Magnetic flux (Φ)
* Peptide PHI (Peptide histidine isoleucine)
* 6-phospho-3-hexuloisomerase, an enzyme
* Phenyl group (Φ), a functional group in organic chemistry
* Pre-harvest interval
* pH(I), the isoelectric point

### Computing

* Xeon Phi, an Intel MIC microprocessor
* Φ (Phi) function, in static single-assignment form compiler design

### Medicine

* Permanent health insurance, against becoming disabled
* Protected health information, in US law

### Other science

* Phi phenomenon, in visual perception
* Krumbein phi scale, for the size of a particle or sediment

## Arts and entertainment

* Phi (KinKi Kids album) (2007)
* Phi (Truckfighters album) (2007)
* Sailor Phi, a villain in the Sailor Moon manga
* Phi, a character in the visual novels Zero Escape: Virtue's Last Reward and Zero Escape: Zero Time Dilemma.
* Phi: A Voyage from the Brain to the Soul, a book by Giulio Tononi (2012)
* Phi, a character from Beyblade Burst Turbo, a TV show written by Hiro Morita

## Organizations

* Packard Humanities Institute
* Paraprofessional Healthcare Institute, a nonprofit organization based in New York City, US
* Pepco Holdings Inc.
* Petroleum Helicopters International, an American commercial helicopter operator
* Philadelphia’s major professional sports teams
   * Philadelphia Eagles of the National Football League
   * Philadelphia 76ers of the National Basketball Association
   * Philadelphia Phillies of Major League Baseball
   * Philadelphia Flyers of the National Hockey League
* Post-Polio Health International
* Phi, a collegiate secret society at Princeton University

## Other uses

* Voiceless bilabial fricative (IPA symbol: ɸ)
* Phi, a village in Sesant, Cambodia
* Phi, ghosts in Thai culture
* Philippines, IOC country code
