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

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

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

The board decided to skip the phase-in process and defer immediately to the national governing bodies for each sport.

From Washington Times • Oct. 5, 2023

A phase-in of the new rates began in 2021.

From Seattle Times • Sep. 14, 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