\ ˈfāz How to pronounce phase (audio) \

Definition of phase

 (Entry 1 of 2)

1 : a particular appearance or state in a regularly recurring cycle of changes phases of the moon
2a : a distinguishable part in a course, development, or cycle the early phases of her career
b : an aspect or part (as of a problem) under consideration
3 : the point or stage in a period of uniform circular motion, harmonic motion, or the periodic changes of any magnitude varying according to a simple harmonic law to which the rotation, oscillation, or variation has advanced from its standard position or assumed instant of starting
4 : a homogeneous, physically distinct, and mechanically separable portion of matter present in a nonhomogeneous physicochemical system
5 : an individual or subgroup distinguishably different in appearance or behavior from the norm of the group to which it belongs also : the distinguishing peculiarity
in phase
: in a synchronized or correlated manner
out of phase
: in an unsynchronized manner : not in correlation


phased; phasing

Definition of phase (Entry 2 of 2)

transitive verb

1 : to adjust so as to be in a synchronized condition
2 : to conduct or carry out by planned phases
3 : to introduce in stages usually used with in phase in new models

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Other Words from phase


phasic \ ˈfā-​zik How to pronounce phasic (audio) \ adjective

Synonyms for phase

Synonyms: Noun

angle, aspect, facet, hand, side

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Phase and Faze

Phase and faze are homophones (words pronounced alike but different in meaning, derivation, or spelling) that may easily be confused. Despite the similarity in pronunciation, these words bear little semantic resemblance to one another.

Although phase can function as a verb – it is found especially in combinations such as phase out, phase in, and phase into, meaning “to end, begin, etc. in phases” – the word is most commonly encountered as a noun, in which it typically carries a meaning related to steps in a process, cycles, or stages of development (as in “phases of the moon”).

Faze is generally used only as a verb, and means “to daunt or disconcert.” It often appears in negative expressions such as “it didn’t faze her a bit” or “nothing fazes him.”

Examples of phase in a Sentence


The project will be done in three phases. He's in the final phase of treatment now. The building project marks a new phase in the town's development. He has been throwing tantrums a lot, but the doctor says it's just a phase. a calendar based on the phases of the moon
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Recent Examples on the Web: Noun

Other portions of Broad Street that are included in the first phase run along Broad from State to Dauphin streets and from Dauphin to Canal streets. al, "At long last, Mobile’s ‘transformative’ Broad Street project to start," 16 Sep. 2019 The first phase of that project, expected to be completed in spring 2020, will include a mix of independent living apartments, assisted living apartments and memory care units. Cathy Kozlowicz, Milwaukee Journal Sentinel, "Proposed senior apartment development in Menomonee Falls could include a fitness center, pool and dog wash," 16 Sep. 2019 The penalty phase of Michael Gargiulo's Los Angeles trial is scheduled to begin on October 7, 2019. CBS News, "The Hollywood Ripper: How "48 Hours" helped crack the case of convicted serial killer Michael Gargiulo," 14 Sep. 2019 The trial in California has yet to move to a penalty phase, but prosecutors will recommend either a death sentence or life in prison without parole. Jessica Villagomez,, "Convicted serial killer Michael Gargiulo, nicknamed the ‘Hollywood Ripper,’ to be featured on an episode of ‘48 Hours’," 12 Sep. 2019 Jurors were told to expect to return on Sept. 9 for the trial’s penalty phase, although a judge said the date could shift. San Diego Union-Tribune, "Man dubbed ‘Boy Next Door Killer’ found sane by jury," 22 Aug. 2019 The jury of seven men and five women, who had deliberated 42 hours and 40 minutes since receiving the case Jan.16, was ordered to return to court at 9 a.m. Thursday for the penalty-phase of the trial. Linda Deutsch, Washington Post, "AP Was There: Charles Manson, followers convicted of murder," 7 Aug. 2019 The penalty phase of the trial will begin Tuesday to determine damages owed by Perry and her co-writers, The New York Times reported. Hollie Silverman, CNN, "Katy Perry's 'Dark Horse' was copied from a Christian rap song, a California jury says," 30 July 2019 The penalty phase is scheduled begin Tuesday with opening arguments, and will ultimately determine how much Perry and other defendants owe for copyright infringement. Andrew Dalton, Fortune, "A Jury Will Decide Damages Owed by Katy Perry for Copy of Christian Rap Song," 30 July 2019

Recent Examples on the Web: Verb

The provisions of the agreement would be phased in over about a year. Patrick Marley, Milwaukee Journal Sentinel, "Sweeping deal with teen inmates will see Wisconsin end use of pepper spray and restrict solitary at teen prisons," 1 June 2018 For three and a half quarters, no one on Carolina’s defense seemed to phase him with a rush. Alaa Abdeldaiem,, "Buccaneers' Defense Stands Tall in Grind-It-Out Victory Over Panthers," 13 Sep. 2019 Coral Gables, Deerfield Beach, Delray Beach, Hallandale Beach and Surfside have banned the straws or are phasing them out. Johnny Diaz,, "Miami Beach latest South Florida city to say no to plastic straws, stirrers," 12 Sep. 2019 Wheeler signed a directive on 10 September that commits the EPA to reduce its funding request for animal studies by 30% by 2025, and to phase them out entirely by 2035. Jeff Tollefson, Scientific American, "Scientists Are Concerned over U.S. Environmental Agency’s Plan to Limit Animal Research," 11 Sep. 2019 Only 20 percent of those companies will phase it out. Ellen Florian, Fortune, "Here’s Why WeWork Won’t be in the S&P 500 After its IPO," 20 Aug. 2019 But starting on Tuesday, the airport will gradually begin phasing them out. CBS News, "San Francisco International Airport rolls out ban on plastic water bottles," 20 Aug. 2019 There's a dash of intensity that comes from the film's villain, Ghost (Hannah John-Kamen), who can phase through anything but fights to control that ability. David Betancourt,, "'Ant-Man and the Wasp' is pretty much exactly like the first movie, and that's a good thing," 2 July 2018 Maryland code required a cost share percentage point drop of more than 5% to be phased in over three financial years. Catalina Righter,, "Carroll schools avoid steep decline in state funding for construction," 14 Sep. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'phase.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of phase


1647, in the meaning defined at sense 1


1904, in the meaning defined at sense 1

History and Etymology for phase


New Latin phasis, from Greek, appearance of a star, phase of the moon, from phainein to show (middle voice, to appear) — more at fancy

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Statistics for phase

Last Updated

16 Oct 2019

Look-up Popularity

Time Traveler for phase

The first known use of phase was in 1647

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More Definitions for phase



English Language Learners Definition of phase

: a part or step in a process : one part in a series of related events or actions
: a short period of time during which a person behaves in a particular way or likes a particular thing
: the shape of the part of the moon that is visible at different times during a month


\ ˈfāz How to pronounce phase (audio) \

Kids Definition of phase

1 : a step or part in a series of events or actions : stage I have completed the first phase of my training.
2 : the way that the moon or a planet looks to the eye at any time in its series of changes with respect to how it shines The new moon and the full moon are two phases of the moon.


\ ˈfāz How to pronounce phase (audio) \

Medical Definition of phase

1 : a particular appearance or state in a regularly recurring cycle of changes
2 : a distinguishable part in a course, development, or cycle the early phases of a disease
3 : a point or stage in the period of a periodic motion or process (as a light wave or a vibration) in relation to an arbitrary reference or starting point in the period
4 : a homogeneous, physically distinct, and mechanically separable portion of matter present in a nonhomogeneous physicochemical system especially : one of the fundamental states of matter usually considered to include the solid, liquid, and gaseous forms
5 : an individual or subgroup distinguishably different in appearance or behavior from the norm of the group to which it belongs also : the distinguishing peculiarity

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More from Merriam-Webster on phase

Thesaurus: All synonyms and antonyms for phase

Spanish Central: Translation of phase

Nglish: Translation of phase for Spanish Speakers

Britannica English: Translation of phase for Arabic Speakers Encyclopedia article about phase

Comments on phase

What made you want to look up phase? Please tell us where you read or heard it (including the quote, if possible).


a topic to which one constantly reverts

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