garden house
A small building or pavilion located in a garden, often used for relaxation, storage, or as a guest house. The term is a direct loan from English and is used in similar contexts.
庭の隅にガーデンハウスを建てた。
We built a garden house in the corner of the garden.
そのガーデンハウスは来客用に使われている。
That garden house is used for guests.