A floor-level sunken courtyard design diagram typically refers to a plan or illustration showing the layout of a sunken garden or courtyard at ground level. This type of design often involves creating a lower level garden area within a larger space, which can provide privacy, a sense of seclusion, and a unique aesthetic. The diagram would include details such as dimensions, plant types, seating areas, and pathways. In architectural and garden design, sunken courtyards are used to enhance the overall ambiance and functionality of a space.