Definition of phase in English:

Share this entry


Pronunciation: /feɪz/


1A distinct period or stage in a process of change or forming part of something’s development: the final phases of the war [as modifier]: phase two of the development
More example sentences
  • The country hopes to pass the next key threshold of 25 chapters and reach the final phase of the negotiation process, he said after the meeting.
  • The final phase of the planning process is orders production, which centers on developing the CHS casualty treatment and evacuation plan.
  • Although agriculture is still caught in the grips of industrialization, corporatization is the final phase of the industrial process.
stage, period, chapter, episode, part, step, point, time, juncture
1.1A stage in a person’s psychological development, especially a period of temporary difficulty during adolescence or a particular stage during childhood: most of your fans are going through a phase
More example sentences
  • Perhaps Jason is right that it is just children going through a phase which will soon stop but somehow I doubt it; it has been going on for years.
  • Separation and individuation are normal and healthy phases of infancy.
  • On the other hand, there remains the issue of identification with the father, which brought to a close the Oedipal phase.
period, stage, time, spell
British informal patch
1.2A stage in the life cycle or annual cycle of an animal.
Example sentences
  • Floods cue fish to spawn, for instance, and trigger certain insects to begin a new phase in their life cycles.
  • Volvox carteri, like all related green flagellates, is haploid in all active phases of the life cycle, which greatly facilitates isolation of mutants.
  • Spined soldier bug adults are strong fliers and, during responsive phases of their life cycle, will fly toward the pheromone from considerable distances.
2Each of the aspects of the moon or a planet, according to the amount of its illumination, especially the new moon, the first quarter, the full moon, and the last quarter.
Example sentences
  • The second condition is that the Sun, Earth and the Moon must also be lined up, corresponding to the phase of the New Moon.
  • A star chart is simply a printed diagram of the sky on a given night or month, with prominent constellations, planets and phases of the moon marked.
  • He discovered moons orbiting Jupiter, phases of Venus, sunspots, and features on the Moon that made it seem more like a planet.
aspect, shape, form, appearance, state, condition
3 Zoology A genetic or seasonal variety of an animal’s coloration: the invertebrate residents of the tundra pass the winter in dormant phase
4 Chemistry A distinct and homogeneous form of matter (i.e. a particular solid, liquid, or gas) separated by its surface from other forms: solid carbon dioxide passes directly into the gas phase without becoming a liquid
More example sentences
  • Intermolecular interactions are most significant in liquid and solid phases where molecules are very close together.
  • Similarly, molecules in the gas phase occasionally strike the surface and are captured by the attraction of molecules in the liquid or solid phase.
  • Such a disappearance of a solid into the gas phase was an intriguing phenomenon.
5 Physics The relationship in time between the successive states or cycles of an oscillating or repeating system (such as an alternating electric current or a light or sound wave) and either a fixed reference point or the states or cycles of another system with which it may or may not be in synchrony: there are two output channels, one fixed in phase and the other variable in phase between 0 and 360 degrees
More example sentences
  • Because we desire to store digital information, our system should have differing phases corresponding to the differing values of the information.
  • The interaction strength and the relative phase of the electric field in neighboring particles both depend on polarization and frequency.
  • Both phy and cry photoreceptors are presumably involved in setting the phase under white light: dark cycles.
5.1Each of the electrical windings or connections of a polyphase machine or circuit.
Example sentences
  • The two phases have different electrical resistance, which represents the binary information.
  • The aluminum nitride material has an interconnected intergranular phase that functions as an electrically conductive phase.
  • A NEW scheme to help small industries in rural areas to upgrade their electricity to 3 - phase has been announced.
6 Linguistics (In systemic grammar) the relationship between a catenative verb and the verb that follows it, as in she hoped to succeed and I like swimming.
Example sentences
  • For talking about two actions or states, which are closely linked, we use two verbs together in phase.
  • Verbs that are followed by other verbs, either the infinitive or the -ing form, are called catenative verbs, or verbs in phase, as in I want to be alone.
6.1A structure containing two verbs in a phase.


[with object]
1Carry out (something) in gradual stages: the work is being phased over a number of years (as adjective phased) a phased withdrawal of troops
More example sentences
  • He believes phasing the withdrawal has its benefits.
  • The development at Newhall Park Road became fully operational in October last year after a three-week move phasing departments from the old site next door to the new building.
  • Councillors suggested possible solutions of phasing the scheme; considering other schemes; and seeking funding from partners.
1.1 (phase something in/out) Introduce something into (or withdraw something from) use in gradual stages: the changes will be phased in over 10 years
More example sentences
  • She however, said the introduction of unleaded fuel would be gradual as it would be phased in slowly beginning this month.
  • He added that any introduction of defibrillators would be phased in, but the aim was for there to be one machine on every engine.
  • The company says changes will be phased in gradually, with half the project completed by the end of this year and fully realised by 2005.
introduce gradually, incorporate by stages, begin using, ease in, start using
eliminate gradually, withdraw/remove/replace gradually, discontinue, get rid of by stages, stop using, ease off, run down, wind down, wind up, deactivate, finish, end
2 Physics Adjust the phase of (something), especially so as to synchronize it with something else: about 70% of the reflections were phased by this method
More example sentences
  • In order to properly phase the two telescopes, adaptive optics on both telescopes removed the distortion caused by the Earth's atmosphere.


See faze (usage)


in (or out of) phase

1Being or happening in (or out of) synchrony or harmony: the cabling work should be carried out in phase with the building work
More example sentences
  • Large species tend to produce their young more in phase with high biomass and after the protein peak.
  • Advisory committees help colleges and universities stay in phase with industry needs.
  • When exiting the corner, the rear wheels turn in phase with the front wheels improving yaw damping.
2 Physics Having or in the same (or different) phase or stage of variation: in a pure inductive circuit voltage and current are always out of phase
More example sentences
  • This current sets up a magnetic field (called the primary field) which oscillates in phase with the transmitter current.
  • A controller senses an input current and an output voltage across an output capacitor for controlling switching to regulate the output voltage and to ensure that the input current is substantially in phase with an input voltage.
  • In running, however, kinetic and potential energy fluctuate in phase with each other.


Early 19th century (in sense 2 of the noun): from French phase, based on Greek phasis 'appearance', from the base of phainein 'to show'.

  • A phase first described an aspect of the moon, but had developed the modern sense of a distinct period by 1701. It is from French phase, based on Greek phasis ‘appearance’.

Words that rhyme with phase

ablaze, amaze, appraise, baize, Blaise, blaze, braise, broderie anglaise, chaise, craze, daze, écossaise, erase, faze, gaze, glaze, graze, Hayes, Hays, haze, laze, liaise, lyonnaise, maize, malaise, Marseillaise, mayonnaise, Mays, maze, phrase, polonaise, praise, prase, raise, raze, upraise

For editors and proofreaders

Line breaks: phase

Share this entry

What do you find interesting about this word or phrase?

Comments that don't adhere to our Community Guidelines may be moderated or removed.