[in-dawr, -dohr]
occurring, used, etc., in a house or building, rather than out of doors: indoor games.

1705–15; aphetic variant of within-door, orig. phrase within (the) door, i.e., inside the house Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
Cite This Source Link To indoor
World English Dictionary
indoor (ˈɪnˌdɔː)
of, situated in, or appropriate to the inside of a house or other building: an indoor tennis court; indoor amusements

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
Cite This Source
Word Origin & History

1711, from within door (opposed to outdoor); the form indoors is first attested 1799 in George Washington's writings.
Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source
Example sentences
The one is an offshoot of the legitimate drama for indoor use, the other for
Outside animal enclosures and an indoor natural history exhibit hall featuring
  live native animals.
Ceiling fans can help regulate indoor temperature, making it more comfortable
  with less energy in summer, winter or in between.
Beat the heat with lots of indoor activities such as live music, storytelling,
  and art and craft projects.
Copyright © 2014, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature