How to say "indoors" in Japanese

• 屋内おくないCommon
  no-adjectiveCovers the ordinary sense of 'indoors': the inside of a building, as opposed to outside. Use it when talking about staying indoors, for example during bad weather.
  屋内おくないにいるのがもったいないぐらいよい天気てんきだった。↗

  It was too nice a day to stay inside.
• 内回りうちまわりCommon
  nounReally means inner tracks or lanes, or going around the inner side of a circle, as with traffic lanes. Its 'indoors' sense is marginal; this is seldom the word you want for being indoors.

For the ordinary sense of 'indoors' — the inside of a building — use 屋内; 「内回り」 really refers to inner tracks, lanes, or circles, and its 'indoors' sense is marginal, so avoid it there.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 屋内おくないindoors
• 内回りうちまわりinner tracks or lanes