Definition of phase in US English:



  • 1A distinct period or stage in a series of events or a process of change or development.

    ‘the final phases of the war’
    as modifier ‘phase two of the development is in progress’
    • ‘The final phase of the planning process is orders production, which centers on developing the CHS casualty treatment and evacuation plan.’
    • ‘‘We are in the administrative phase of the process at the moment, where we are getting the bones of the business together,’ Mara said.’
    • ‘As the peace process enters its final phase I think we can be hopeful about its outcome.’
    • ‘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 new-technology approach also places the design control requirements into the appropriate phase of the development process.’
    • ‘The Taiwanese economy has gone through three distinct phases of development.’
    • ‘Wheat crops should be managed to have a leaf canopy sufficient to intercept most of the sunlight during the final phases of development: ear emergence through to the end of grain fill.’
    • ‘In the first phase of his reform process, he has directed each institution to come up with two or three major projects that can be completed by December.’
    • ‘Over the study period, two distinct phases could be discerned with respect to population numbers of different age/size classes.’
    • ‘The fifth phase, the final development of the project, will feature semi-detached houses.’
    • ‘Once a blockbuster had made a solid purchase on a block, it was relatively easy to complete the final phase of the blockbusting process.’
    • ‘With this letter, we enter a new phase of the nomination process, in which the opponents have something very substantial to talk about.’
    • ‘The first phase of the development process will involve the department's planning and building unit publishing a discussion paper on a target areas.’
    • ‘The club's new pitches and dressing-rooms were in the final phase of development and it was envisaged that they would be completed by May, 2004.’
    • ‘All businesses go through distinct phases of development, and each shift presents new challenges.’
    • ‘Although agriculture is still caught in the grips of industrialization, corporatization is the final phase of the industrial process.’
    • ‘This marks the third and final phase of the development process, decline in development intensity.’
    • ‘Regardless of the method used, the final phase of the research process is disseminating the findings.’
    • ‘The PHA document is updated as necessary throughout the early phases of the development process.’
    • ‘These findings confirm the existence of two distinct phases in vegetative development.’
    stage, period, chapter, episode, part, step, point, time, juncture
    View synonyms
    1. 1.1 A stage in a person's psychological development, especially a period of temporary unhappiness or difficulty during adolescence or a particular stage during childhood.
      ‘you are not obsessed, but you are going through a phase’
      • ‘We come now to the vexed questions of the Oedipus complex, childhood amnesia, and the so-called latency period, which is supposed to follow the Oedipal phase.’
      • ‘So when you told us that day that you no longer wanted to be a lawyer, we thought you were going through a phase.’
      • ‘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.’
      • ‘Future research should include youths from various cultural and socioeconomic backgrounds, as well as those in the early and late phases of adolescence.’
      • ‘The Good Body treats eating disorders as though they are temporary, adolescent phases but anorexia and bulimia can be fatal diseases.’
      • ‘It was generally believed that I was going through a phase, or trying to be different.’
      • ‘Puberty is the first phase of adolescence, the time when sexual maturity becomes evident.’
      • ‘On the other hand, there remains the issue of identification with the father, which brought to a close the Oedipal phase.’
      • ‘But in this preoedipal phase of psychological development there is no evidence that masculinity or femininity will follow predetermined routes.’
      • ‘Adolescents' developmental phase and their available ego strength determine their willingness to seek help.’
      • ‘For males, we also found that their parental bond became somewhat less positive in the transition from the early to the middle phase of adolescence.’
      • ‘Leta is going through a phase where she doesn't like to be put down.’
      • ‘As you go through the book we think Holden will change his easy-come-easy-go attitude to life and that his alienation is just a passing phase of adolescence.’
      • ‘Adolescence is the exciting phase of transition when human beings start developing the cognitive ability to form abstract thoughts.’
      • ‘This phase sees the active development of ideas and a movement towards a more balanced life and diversified set of interests, relationships, and routines.’
      • ‘Judging by the standard of the ‘artwork’ on display these people are not artists - just children going through a phase.’
      • ‘He's going through a phase where he doesn't like to be the center of attention (at least outside of the house).’
      • ‘I convinced myself that she's just going through a phase and that nothing was wrong.’
      • ‘Am I a rebellious teenager whose going through a phase in life?’
      period, stage, time, spell
      View synonyms
    2. 1.2 Each of the separate events in an eventing competition.
      • ‘In eventing, the first of the two championship divisions, the CCI * for junior riders, began with its dressage phase.’
      • ‘The morning started off with the final phase of the eventing competition, the show jumping.’
      • ‘Davidson was the clear winner of the dressage phase, finishing with a score of 47.21.’
      • ‘As these are newer bits, the USEA was interested to learn more about them when considering approving them for use in the dressage phase of eventing.’
  • 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.

    • ‘The phases of the Moon have often been associated with madness, giving rise to the English word ‘lunatic’.’
    • ‘The Prince of Wales's interest in organic gardening has turned an even deeper shade of green with his decision to experiment with planting crops according to the phases of the moon.’
    • ‘The project included work on the Earth, Sun and Moon, and investigating the solar system, the phases of the moon and different types of orbit.’
    • ‘Our grandparents who planted and pruned according to phases of the moon are early examples of farmers using natural influences to nurture plant growth.’
    • ‘She wrote at length on the four humours and on the temperaments of people according to the phase of the Moon in which they were conceived.’
    • ‘I also at a very young age fell in love with the moon in all its phases, though the full moon always drew me out.’
    • ‘These calculations are made according to moon phases, times and tides.’
    • ‘In a prolific career, Galileo's discoveries, including phases of Venus and moons orbiting Jupiter dealt a death blow to geocentric theory.’
    • ‘Soon her palm resembled a chart of lunar phases, four thin moons, their tiny scarlet crescents crossing the lines of galaxies and Fate.’
    • ‘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.’
    • ‘Their constantly changing work schedule revolves around the many phases of the moon and the tides.’
    • ‘The determination of the date of Easter is governed by a computation based on the vernal equinox and the phase of the moon.’
    • ‘You might consider doing this ritual destruction on a New Moon, as it is a phase of the moon commonly held in association with new beginnings.’
    • ‘The second condition is that the Sun, Earth and the Moon must also be lined up, corresponding to the phase of the New Moon.’
    • ‘The play is to be staged during the full moon phase of June 2005.’
    • ‘The residents largely believed, however, in an ancient prophecy that said the city was safe from its enemies during the waxing phase of the Moon.’
    • ‘Galileo's most critical telescopic discovery was that Venus had phases like the Moon.’
    • ‘He discovered moons orbiting Jupiter, phases of Venus, sunspots, and features on the Moon that made it seem more like a planet.’
    • ‘They presented a guide to the movement of the planets, the phases of the Moon and even the mythology of some famous constellations.’
    • ‘I have caught many large fish during the full or new moon phase and while the catch rate is not as good as on other nights, trout still take my offering.’
    aspect, shape, form, appearance, state, condition
    View synonyms
  • 3Zoology
    A genetic or seasonal variety of an animal's coloration.

  • 4Chemistry
    A distinct and homogeneous form of matter (i.e. a particular solid, liquid, or gas) separated by its surface from other forms.

    • ‘Similarly, molecules in the gas phase occasionally strike the surface and are captured by the attraction of molecules in the liquid or solid phase.’
    • ‘The triple point of water is the temperature at which gas, liquid and solid phases are in equilibrium - just above freezing.’
    • ‘Such a disappearance of a solid into the gas phase was an intriguing phenomenon.’
    • ‘Intermolecular interactions are most significant in liquid and solid phases where molecules are very close together.’
    • ‘How can water co-exist at three phases (solid, liquid and gas)?’
  • 5Physics
    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.

    • ‘Both phy and cry photoreceptors are presumably involved in setting the phase under white light: dark cycles.’
    • ‘The interaction strength and the relative phase of the electric field in neighboring particles both depend on polarization and frequency.’
    • ‘The RHIC detectors will soon be able to record energetic photons emitted in quark-antiquark interactions in the plasma phase.’
    • ‘Because we desire to store digital information, our system should have differing phases corresponding to the differing values of the information.’
    • ‘During the low-pressure phase of each sound wave, bubbles expanded rapidly.’


[with object]
  • 1Carry out (something) in gradual stages.

    ‘the work is being phased over a number of years’
    • ‘He believes phasing the withdrawal has its benefits.’
    • ‘At least with United Utilities local traders were fully consulted and the work was phased to minimise disruption to business.’
    • ‘I was speaking to some ladies during the week and they told me they would be doing the full course but will be phasing it over three days.’
    • ‘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. 1.1phase something in/out Introduce something into (or withdraw something from) use in gradual stages.
      ‘our armed forces policy was to be phased in over 10 years’
      • ‘She however, said the introduction of unleaded fuel would be gradual as it would be phased in slowly beginning this month.’
      • ‘The UK representatives said that although the UK development program is now focused on the provision of high quality technical assistance, it would be phased out gradually over time as local capacity increases.’
      • ‘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.’
      • ‘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 rules will be phased in gradually to cover smaller businesses.’
      introduce gradually, incorporate by stages, begin using, ease in, start using
      eliminate gradually, remove gradually, replace gradually, withdraw gradually, discontinue, get rid of by stages, stop using, ease off, run down, wind down, wind up, deactivate, finish, end
      View synonyms
  • 2Physics
    Adjust the phase of (something), especially so as to synchronize it with something else.

    • ‘In order to properly phase the two telescopes, adaptive optics on both telescopes removed the distortion caused by the Earth's atmosphere.’


See faze


  • in (or out of) phase

    • Being or happening in (or out of) synchrony or harmony.

      ‘the cabling work should be carried out in phase with the building work’
      • ‘Advisory committees help colleges and universities stay in phase with industry needs.’
      • ‘This improvement in keeping the moon in phase with the month had the unfortunate effect of taking the year even further out of phase with the period of the recurring seasons.’
      • ‘When exiting the corner, the rear wheels turn in phase with the front wheels improving yaw damping.’
      • ‘Large species tend to produce their young more in phase with high biomass and after the protein peak.’
      • ‘It's not just a matter of there being more light; when you've got more than one of these things going in close proximity, and they're operating out of phase with each other, they're a hell of a lot more dazzling than the lights on a single car.’


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