noun
exterior hallway; open-air corridor
Refers to an outdoor hallway, typically along the outside of an apartment building, providing access to individual units. Common in Japanese multi-family housing.
このアパートは外廊下なので、雨の日は少し濡れます。
This apartment has an exterior hallway, so you get a little wet on rainy days.
外廊下から各部屋に入るタイプの集合住宅です。
It's a type of apartment building where you enter each unit from an open-air corridor.