Floor sinking courtyard drawing

Quick answer：

A floor sinking courtyard, also known as a sunken garden, is a type of outdoor space that is designed to be lower than the surrounding ground level. These courtyards are often found in residential buildings and are used for outdoor leisure activities. The design typically includes landscaping elements such as plants, water features, and seating areas. They can provide a sense of privacy and a tranquil retreat within the urban environment.