Phase

In physics

• 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

In other sciences

• 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)