noun, noun or participle which takes 'suru'
drying laundry outside; outdoor drying
Refers to hanging laundry outdoors to dry, as opposed to using a dryer or drying indoors. Commonly used as a noun or with する.
今日は天気がいいから、洗濯物を外干ししよう。
The weather is nice today, so let's dry the laundry outside.
花粉の季節は外
It's better to avoid drying laundry outside during pollen season.