indoor

American  

[in-dawr, -dohr] / ˈɪnˌdɔr, -ˌdoʊr /

adjective

1. occurring, used, etc., in a house or building, rather than out of doors.

   indoor games.

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indoor British  

/ ˈɪnˌdɔː /

adjective

1. of, situated in, or appropriate to the inside of a house or other building

   an indoor tennis court

   indoor amusements

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Etymology

Origin of indoor

1705–15; aphetic variant of within-door, originally phrase within ( the ) door, i.e., inside the house

Explanation

Use the adjective indoor to describe something that happens or is used inside a building or house. Your indoor furniture is probably a little fancier than your plastic outdoor furniture. Indoor sports are the ones you play inside, like ping pong and floor hockey — beach volleyball is not an indoor sport. Your indoor voice is likewise the one you use in your house or classroom, a quieter voice than when you holler across a parking lot to your friend in his convertible. Indoor, which has been used since the 18th century, is a shortened form of the phrase within door.

Example Sentences

“It’s the only detention center in the country that doesn’t have an indoor waiting area,” she said.

From Slate • May 29, 2026

After an injury-disrupted 2025, the 24-year-old says she has not missed a single session during the best winter training block of her career - as evidenced when she smashed the world indoor record in February.

From BBC • May 29, 2026

A 28-year-old woman also died of heatstroke at an indoor athletics meeting in the eastern Rhone region.

From Barron's • May 25, 2026

The Beverly Hills mansion features a wide range of custom amenities, including an indoor sports complex, complete with basketball and pickleball courts, a fully equipped gym, a boxing ring, a sports lounge, and a bar.

From MarketWatch • May 20, 2026

After using the toilet—Aunt Rose had indoor plumbing, thankfully, even if she didn’t have electricity—Ophie tiptoed downstairs to the kitchen.

From "Ophie's Ghosts" by Justina Ireland

Related Words

• private