noun
Refers to the building or structure housing a windmill, not just the machinery itself.
オランダの田園地帯には風車小屋が点在している。
Windmills dot the Dutch countryside.
風車 refers to the windmill as a machine or device, while 風車小屋 specifically means the building that houses it.
Compound of 風車 (windmill) + 小屋 (hut, small building).