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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

TK costs about $3.7 billion annually and became fully operational this year after its four-year phase-in.

From Los Angeles Times ● Dec. 3, 2025

After the phase-in ends in 2030, MPG ratings for EVs will be about 65% lower.

From Seattle Times ● Apr. 9, 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 Samuel Vaknin

For Kabra, though, who outlined his thoughts in a note to clients Thursday, “the biggest deleveraging phase in Korean equities is nearly complete.”

From MarketWatch ● Aug. 6, 2026

He highlighted the battle against the fires had entered a "new phase" in the Gironde region, saying "the evacuated individuals are gradually returning to their homes".

From BBC ● Aug. 4, 2026

The WBG said the five-year CPF "marks a new phase in a 45-year partnership," as China moves from needing financing to primarily requiring technical assistance and knowledge sharing.

From Barron's ● Jul. 23, 2026

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

From Science Daily ● Jul. 3, 2026

“I never planned to be a flight attendant forever. This is a new phase in my life.”

From "The Miseducation of Cameron Post" by emily m. danforth