The superstructure of a building is the part that is entirely above its foundation or basement. It is the part of the building that is above ground level, and it usually serves the purpose of the building's intended use.
The substructure of a building is the lower portion that transmits the load of the superstructure into the supporting soil. Also known as the foundation, the substructure is in direct contact with the ground supporting the building and is usually below ground level. The plinth is the portion of the building between the ground level and the surface of the floor immediately above the ground. It is part of the superstructure.