2 floor with sunken courtyard effect

Quick answer：

The description refers to a residential floor design that includes a sunken courtyard. A sunken courtyard is a garden or courtyard that is lower in elevation than the surrounding ground level. This design feature can provide privacy, enhance the aesthetic appeal of the building, and create a serene indoor-outdoor living space. In architectural design, sunken courtyards are often used to maximize natural light and ventilation while maintaining a sense of seclusion.