# phase in

CEFR B2 · Phrasal verb

Source: https://englishreference.com/word/phase-in
Updated: 2026-10-22

## Definition

to start using or introducing something new slowly, in small steps, rather than all at once.

For teachers: to introduce a new system, law, or product gradually over a period of time. This transitive verb implies a planned, incremental implementation.

## Examples

- The company phases in the new rules over several months.
- Instead of changing everything overnight, the school decided to phase in the new curriculum over three years.
- The government announced a plan to phase in stricter environmental regulations to allow local industries sufficient time to adapt their manufacturing processes.

## Pitfalls

- Not "The company will phase in it." but "The company will phase it in." — When the object is a pronoun, it must be placed between the verb and the particle.

## Usage notes

- This verb is separable, meaning the object can be placed between the verb and the particle.
- Teaching tip: Contrast this with 'phase out' to help students learn the pair as a logical set for discussing change management.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.