Both Uses of

arbor

in

Sense and Sensibility

Then, there is a dove-cote, some delightful stew-ponds, and a very pretty canal; and every thing, in short, that one could wish for; and, moreover, it is close to the church, and only a quarter of a mile from the turnpike-road, so 'tis never dull, for if you only go and sit up in an old yew arbour behind the house, you may see all the carriages that pass along.†
Chpt 30

unconventional spelling: This is a British spelling. Americans use arbor.

The good understanding between the Colonel and Miss Dashwood seemed rather to declare that the honours of the mulberry-tree, the canal, and the yew arbour, would all be made over to HER; and Mrs. Jennings had, for some time ceased to think at all of Mrs. Ferrars.†
Chpt 32 *

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)
Much more rarely, an arbor can be used as a proper noun to reference a location. As a common noun, it can also reference various types of rotating machine shafts.