# indoor

/ˈɪnˌdɔɹ/ (US) · /ˈɪndɔː/ (UK) · CEFR B1 · Adjective

Source: https://englishreference.com/word/indoor
Updated: 2026-05-02

## Definition

located, used, or happening inside a building. You use this to describe things that are protected from the weather outside.

For teachers: situated, conducted, or used within the interior of a building. Attributive in function; it must precede the noun it modifies.

## Examples

- The hotel has a large indoor pool.
- Because of the heavy rain, the school moved the sports day to an indoor gym.
- The facility offers various indoor activities, including rock climbing and tennis, allowing athletes to train consistently regardless of the seasonal weather conditions.

## Pitfalls

- Not "The cat is indoor." but "The cat is indoors." — Indoor is an adjective used before nouns; indoors is the adverb used to describe where an action happens or where something is located.

## Usage notes

- The adjective is attributive, meaning it is placed before a noun (e.g., 'indoor plants') and is not typically used after a linking verb like 'is'.

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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.