definition
strict definition
garden floor
An otherwise regular floor partly below and partly above the surrounding ground surface at the building perimeter.
A garden floor is an otherwise regular but partly sunken floor, which is partly below the surface of the earth at the building's perimeter, and partly above it. The windows of a garden floor usually open onto a dug-out trough, or are located close to the ceiling.
The level crosses the ground surface rather than lying fully underground. That partial exposure distinguishes it from a basement under the floor-type definitions.
A window trough or high-set windows are usual consequences of the partly sunken position. Their presence is not a separate requirement for every garden floor.