Pergola

A pergola is a frame of posts holding up open rafters, with no solid roof. It is not a gazebo (which is roofed and usually round) or a simple arbor (which is small and mostly an entry feature). A pergola is sized to sit under.

What it does is mark a room without walling it off. It throws striped shade, gives climbing plants like wisteria or grape something to run along, and anchors a seating or dining area so the space feels deliberate instead of like furniture parked on a slab.

The honest limit is shade. Bare rafters cut glare but will not keep you dry, and a south-facing pergola needs either a vine that takes a few seasons to fill in or a fitted shade cloth to be comfortable at midday.