A pergola is a garden feature forming a shaded walkway, passageway, or sitting area of vertical posts or pillars that usually support cross-beams and a sturdy open lattice, often upon which woody vines are trained. The origin of the word is the Late Latin pergula, referring to a projecting eave. As a type of gazebo, it may also be an extension of a building or serve as protection for an open terrace or a link between pavilions. They are different from green tunnels.[how?]
Pergolas are sometimes confused with arbours, and the terms are often used interchangeably. An arbour (or arbor in American English) is generally regarded as a wooden bench seat with a roof, usually enclosed by lattice panels forming a framework for climbing plants. A pergola, on the other hand, is a much larger and more open structure and does not normally include integral seating