belvedere, either a type of summer-house or a roofed, detached porch-like structure, usually in a yard, park or lawn
A small summerhouse or pavilion with a view, or a belvedere on the roof of a house
A gazebo is a small building with open sides. Gazebos are often put up in gardens so that people can sit in them to enjoy the view. Lookout in the form of a turret, cupola (small, lanternlike dome), or garden house set on a height to give an extensive view. Few late-18th-and 19th-century rustic gazebos survive, but 17th-century turrets built up in an angle of the garden wall are not uncommon. The term now often refers specifically to a freestanding roofed structure, typically octagonal, with open or latticework sides