Residential sinking courtyard illustration

Quick answer：

A sinking courtyard in residential architecture refers to a courtyard that is below the level of the surrounding ground. This design element is often used to create a sense of privacy, separation from the outside world, and a tranquil space for residents. Sinking courtyards can be found in traditional Chinese gardens, where they are known as 'sunken gardens.' These gardens often feature lush vegetation, ponds, and other natural elements to enhance the serene atmosphere.