# be in on

CEFR C1 · Phrasal verb

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

## Definition

to be part of a group that knows a secret or is involved in a private plan.

For teachers: to be privy to or a participant in a secret, scheme, or specific activity.

## Examples

- Are you in on the surprise party?
- Only a few managers were in on the plan to sell the company before the news went public.
- While the public remained unaware of the impending merger, several high-level executives had been in on the negotiations for months.

## Pitfalls

- Not "He was in the secret." but "He was in on the secret." — the preposition 'on' is required to show participation in a plan or secret.

## Usage notes

- usually followed by a noun phrase representing a secret, joke, or plan.
- Teaching tip: contrast with 'be in' (to be at home/office); the addition of 'on' shifts the meaning from physical location to shared knowledge or participation.

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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.