外そと窓まど

noun

outer window

Refers to the exterior window in a double-window setup, often contrasted with 内窓 (inner window). Common in architectural and home improvement contexts.

See also: 内窓

• 外そと窓まどと内うち窓まどの間あいだにブラインドを取とり付つけた。

  I installed blinds between the outer window and the inner window.