sliding glass door; patio door
A large glass door that opens onto a garden, balcony, or terrace. Common in modern Japanese houses.
You can go out to the garden through the sliding glass door in the living room.
When you open the patio door, a nice breeze comes through.
floor-level sweep-out opening
A small opening at floor level, traditionally used to sweep dirt directly outside. Now mostly a historical or traditional architectural feature.
Old Japanese houses had a small cleaning opening called a 掃き出し窓 at floor level.