indoor
Americanadjective
adjective
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
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The date meant that the premiere would take place not in an indoor hall as first intended, but at Tanglewood, the Boston Symphony’s storied summer home.
From The Wall Street Journal ● Jul. 7, 2026
Franklin D Roosevelt swam in an indoor pool which today is the White House press room, while Gerald Ford enjoyed an outdoor pool, Trump said.
From Barron's ● Jul. 3, 2026
That main living space opens up directly to the backyard courtesy of the glass walls that slide open to break the barrier between the indoor and outdoor areas.
From MarketWatch ● Jul. 1, 2026
The couple have said almost nothing about it, but you can't book New York's biggest indoor concert venue for an entire weekend without causing a few whispers.
From BBC ● Jul. 1, 2026
“Well, that monstrosity that Mr. Lemoncello constructed isn’t really a library, Andrew. It’s an indoor amusement park.”
From "Mr. Lemoncello's Library Olympics" by Chris Grabenstein
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
