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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

There also is a gradual phase-in over several years.

From Los Angeles Times ● Sep. 13, 2025

Under the proposed measure, midsize companies with 15 to 500 workers would have a multiyear phase-in period, meeting the large employers rate in July 2026.

From Seattle Times ● Feb. 13, 2024

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

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

Volumes should be slightly down, as the 296 GTB phases out and the 849 Testarossa and Amalfi are only starting to phase in.

From The Wall Street Journal ● Jul. 7, 2026

"I know I have reached a certain phase in my career," Modric said recently.

From BBC ● Jul. 3, 2026

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

From Science Daily ● Jul. 3, 2026

But SLB probably offers more upside during a postwar mobilization phase in the region.

From Barron's ● May 28, 2026

We now know that Cepheids throb as they do because they are elderly stars that have moved past their "main sequence phase," in the parlance of astronomers, and become red giants.

From "A Short History of Nearly Everything" by Bill Bryson