summer house 
noun
A small building in a garden, used for sitting in during fine weather.There are three patio areas, a summer house and garden shed....
- Many of the school's sixth formers helped with the work on the summer house and surrounding garden.
- The building with which this appeal is concerned was originally a summer house in the garden of the Trust's property.
Synonyms
gazebo, pavilion, belvedere, arbour, bower, pergola
archaic, Turkey & Iran kiosk