# rule in

CEFR B2 · Phrasal verb

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

## Definition

to decide that something is a possible choice or explanation after thinking about it.

For teachers: to include something as a valid possibility or factor in an investigation or decision. Transitive and optionally separable, it is frequently used as the logical counterpart to 'rule out'.

## Examples

- The investigators are trying to rule in all possible causes of the fire.
- Although the main theory is mechanical failure, the engineers haven't ruled in human error as a factor yet.
- The committee must rule in every viable candidate before the final interview stage to ensure a fair and comprehensive selection process.

## Pitfalls

- Not "We cannot rule in it yet." but "We cannot rule it in yet." — When the object is a pronoun, it must be placed between the verb and the particle.

## Usage notes

- Usually used in the context of investigations, medical diagnoses, or formal decision-making.
- Teaching tip: Contrast this with 'rule out' to show how options are managed during a logical process of elimination.

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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.