Phase

Phase or phases may refer to:

In science

Phase (waves), the position of a point in time (an instant) on a waveform cycle
Phase (matter), a physically distinctive form of a substance, such as the solid, liquid, and gaseous states of ordinary matter—also referred to as a "macroscopic state"

Phase transition, the transformation of a thermodynamic system from one phase to another

- Mobile phase in chromatography
- Stationary phase (chemistry) in chromatography
Phase space, a mathematical space in which each possible state of a physical system is represented by a point—this point is also referred to as a "microscopic state"
- Phase space formulation, a formulation of quantum mechanics in phase space
Polyphase system, a means of distributing alternating current electric power in multiple conducting wires with definite phase offsets
- Single-phase electric power, distribution of AC electric power in a system where the voltages of the supply vary in unison
- Three-phase electric power, a common method of AC electric power generation, transmission, and distribution
  - Three-phase, the mathematics of three-phase electric power
Phase problem, the loss of information (the phase) from a physical measurement
Phase factor, a complex scalar used in quantum mechanics
Continuous Fourier transform, the angle of a complex coefficient representing the phase of one sinusoidal component
Instantaneous phase, generalization for both cyclic and non-cyclic phenomena

Archaeological phase, a discrete period of occupation at an archaeological site
Gametic phase, in genetics, the relationship between alleles at two loci
Lunar phase, the appearance of the Moon as viewed from the Earth
Planetary phase, the appearance of the illuminated section of a planet
In biology, a part of the cell cycle in which cells divide and reproduce
Color phase, in biology, a group of individuals within a species with a particular coloration
Phase (syntax), in linguistics, a cyclic domain (proposed by Noam Chomsky)

Phase (band), a Greek alternative rock band
Phases (band), an indie pop American band, formerly known as JJAMZ
Phases (The Who album), a box set of albums by The Who
Phases (album), a 2015 acoustic album by I See Stars
"Phases" (Buffy the Vampire Slayer), a 1998 episode of the TV series Buffy the Vampire Slayer
Phases (.hack), fictional monsters in the .hack franchise
Phase IV, a 1974 science fiction movie directed by Saul Bass
Phase, an incarnation of the DC Comics character usually known as Phantom Girl
Phaze, an alternate world in Piers Anthony's Apprentice Adept series
Phase (album), a debut studio album by an English singer Jack Garratt

Phase 10, a card game created by Fundex Games
Phase (video game), a 2007 music game for the iPod developed by Harmonix Music Systems
Phase (combat), usually a period of combat within a larger military operation
A musical composition using Steve Reich's phasing technique