Ci talk:1013917817
From Wenlin Dictionaries
Common word. It means "outdoors." E.g. 經常發生屋外下大雨,... But I suppose you will want to retain "outside of a room" just in case. ABC's def is based on Kuraishi's def: "heya no soto, okugai" (vkura581a8). The first term "heya no soto" can mean either "outside the room" or "outdoors", but "okugai" is unambiguously "outdoors".
Other examples: 屋外有鬼,家中也有鬼。|| 還常在屋外樹上見到貓頭鷹徘徊佇留,|| 屋外容器切勿積水,以免孳生蚊蟲。