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.