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• phase-in
  phase-in

  noun

  an act or instance of phasing in; gradual introduction or implementation.
• phase in
  phase in

  verb

  (tr, adverb) to introduce in a gradual or cautious manner

phase-in

American  

[feyz-in] / ˈfeɪzˌɪn /

noun

1. an act or instance of phasing in; gradual introduction or implementation.

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phase in British  

verb

1. (tr, adverb) to introduce in a gradual or cautious manner

   the legislation will be phased in over two years

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phase in Idioms  

1. Introduce one stage at a time. For example, New technology must be phased in or the office will be overwhelmed. The antonym is phase out, meaning “to bring or come to an end, one stage at a time,” as in The department is phasing out all the older computers. [Mid-1900s]

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Etymology

Origin of phase-in

Noun use of verb phrase phase in

Example Sentences

See Examples For:

phase-in phase in

The 50% U.S. content proposal is likely to be viewed skeptically by many automakers, who would struggle to source half of their content from U.S. sources, particularly if there is only a short phase-in period.

From The Wall Street Journal ● May 29, 2026

In 2021, the local air district and Air Resources Board agreed to a gradual phase-in of the law, starting with large farm operations, with the goal of a near-complete burn ban by Jan. 1, 2025.

From Los Angeles Times ● Jan. 3, 2025

FDA proposes a phase-in of the new rules over 4 years, but its specific demands aren’t yet clear.

From Science Magazine ● Dec. 12, 2023

Employers with 15 to 500 workers would have a multiyear phase-in period.

From Seattle Times ● Nov. 30, 2023

Important commodities - such as sugar, rice and bananas - are virtually excluded by long phase-in periods.

From The Belgian Curtain Europe after Communism by Vaknin, Samuel

Burnham announced last week that he was pausing the scheme, which would have seen about 700 prisoners freed in the first phase in September, following a backlash from survivors and victims.

From BBC ● Jul. 27, 2026

Another planned facility, Cosmic Explorer, is currently in the design phase in the United States.

From Science Daily ● Jul. 3, 2026

The commissioners plan to develop a five-year plan to phase in state funding, along with enforceable standards like caseload limits and access to defense investigators.

From Los Angeles Times ● Jun. 21, 2026

The strike marked a new phase in U.S. military action in the region, following the capture of Nicolás Maduro and a new cooperation agenda with Venezuela.

From The Wall Street Journal ● Jun. 13, 2026

This letter signifies the start of a crucial new phase in Lawrences transformation from hands-on physicist to fund-raising impresario.

From "Big Science" by Michael Hiltzik