# phase

Pronunciation: say "FAYZ" /feɪz/

## Noun

1. A distinct part of a sequence or cycle that takes place over a period of time.
   - Simple: One clear part of something that happens in steps over time.
   - _The rollout moved into its second phase last month._
   - _Teething is just one phase in a child's early development._
3. One of the recurring appearances of a celestial body's illuminated disk, defined by how much of it is lit or whether it is visible at all.
   - Simple: The shape of the lit-up part of the Moon or a planet as it changes over time.
   - _Through a small telescope, Venus can be seen going through phases much like the Moon's, from a thin crescent to a nearly full disk._
   - _Farmers once timed their planting by the phase of the Moon, sowing some crops only while it was growing fuller._
4. A distinct portion of a material system set apart by its chemical makeup, physical state, or crystal structure, with a sharp boundary from neighboring portions.
   - Simple: A part of a material that is the same all through, such as ice, liquid water, or steam.
   - _Oil and water separate into two distinct phases when you stop stirring._
   - _At high pressure, carbon can crystallize into a diamond phase._
5. A particular aspect or side of something, as it appears to the eye or as it is considered in the mind.
   - Simple: One side of something: one way it looks, or one part of it you think about.
   - _He knows every phase of the business, from buying stock to keeping the books._
   - _Her research touches on nearly every phase of the problem, from the chemistry of the soil to the money the farms lose._
6. A particular point or portion in a recurring series of changes, such as the motion of a particle in a wave or vibration, often contrasted with the portion on the opposite side of equilibrium.
   - Simple: One point in the repeating motion of a wave or vibration.
   - _When two sound waves are in phase, their peaks line up and reinforce each other._
   - _A small delay shifted the signal's phase by half a cycle._
9. In a polyphase alternating-current power system, one of the line conductors other than the neutral, or the alternating current it carries.
   - Simple: In a power system with several alternating currents, one of the live wires, or the current it carries.
   - _The motor draws balanced current from all three phases of the supply._
   - _A fault on one phase tripped the protective breaker._

## Verb

2. To start or stop something gradually over time, bringing it in or taking it out in stages.
   - Simple: To start or stop doing something slowly, a little at a time.
   - _Managers chose to phase in the changes department by department._
   - _The factory plans to phase out coal use within a decade._
7. Alternative spelling of faze. Widely considered an error; careful writers use faze. *(nonstandard)* — Alternative spelling of faze
   - Simple: Alternative spelling of faze. Many people see it as a mistake, so write faze instead.
   - _The harsh criticism didn't phase him in the slightest._
   - _Large crowds never phase seasoned performers._
8. To pass into or through a solid object, moving through solid matter as if it offered no resistance.
   - Simple: To move into or through a solid object, as if going straight through it.
   - _The spirits in the story phase through locked doors at will._
   - _With the device active, she could phase into the vault undetected._

## Other meanings

- (noun) The counterclockwise angle, measured from the positive real axis, to the vector pointing to a complex number on an Argand diagram.
- (noun) In certain organisms, one of the characteristic color forms within a species, unrelated to seasonal or sexual differences and often unrelated to age.
- (noun) In rugby union, the period of play between one breakdown and the next.
- (noun) A distortion produced when different frequencies propagate at different speeds and so arrive out of step with one another.
- (verb) To fire or operate a phaser, the energy weapon of science fiction.
- (noun) In genetics, the arrangement of alleles at linked sites across a pair of chromosomes, that is, which variants lie together on the same chromosome copy.
- (verb) In genetics, to work out the haplotypes in genetic data when the genotypes are already known.

## Origin

φαίνω (phaínō, 'to cause to appear') gave Ancient Greek φάσις (phásis, 'an appearance'), which New Latin took over as phasis, the source of the English word. Compare phantasm; see also face.

Source: DictionaryAI, https://dictionaryai.com/define/phase (written from Wiktionary data, CC BY-SA 4.0: https://creativecommons.org/licenses/by-sa/4.0/).