All 3 Uses

arbor
in
The Soloist
(Edited)

The patio is an oasis of trees and benches, a manicured lawn and bougainvillea cascading over a wooden arbor.
Chpt 2.15 *

arbor = a framework that supports climbing plants; or a shady rest area made by such a framework or by trees and shrubs
I ask Nathaniel as we stroll over to the arbor.
Chpt 2.15
I call Stuart Robinson while Nathaniel sets up under the arbor and tell him it looks like something has died in the apartment.
Chpt 2.19

Definitions:

(1) (arbor as in: shaded arbor)
a framework that supports climbing plants; or a shady rest area made by such a framework or by trees and shrubs

The framework of an arbor is generally thought of as a wood lattice made to support vines, but it can also be a natural framework such as trees.
(2) (meaning too rare to warrant focus)
Less commonly arbor can be used as a proper noun to reference a location such as Ann Arbor, Michigan. As a common noun, it can also reference various types of rotating machine shafts.