# keep in

CEFR B1 · Phrasal verb

Source: https://englishreference.com/word/keep-in
Updated: 2026-04-24

## Definition

to make someone stay inside a place, usually as a punishment or for safety.

For teachers: to detain someone within a building or room; frequently used in educational contexts regarding detention or in medical contexts regarding patient confinement.

## Examples

- The teacher kept the students in after school.
- Because of the heavy rain, the coach decided to keep the players in for a theory session.
- The hospital staff decided to keep the patient in for observation to ensure no further complications arose from the surgery.

## Pitfalls

- Not "The teacher kept in the students." but "The teacher kept the students in." — while technically possible, when the object is a person, it almost always goes between 'keep' and 'in'.

## Usage notes

- usually takes a person as the object; often implies a lack of choice for the person being kept.
- Teaching tip: contrast with 'keep out' (preventing entry); in a school context, 'keep in' is the standard term for the act of giving a student detention.

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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.