foundation system
The type of structure which gives structural support to a building beneath its lowest floor or ground base.
A structure's foundation is the structure which supports it in the ground. The forms and materials of foundations vary according to ground conditions, frame material, framing system, and other factors.
In large structures, the foundation (or basement) wall does not play a significant role in carrying the structural loads above it - this wall mainly resists the lateral load of the soil (and any water) that the basement is constructed in. Foundation systems for large buildings are almost always built with concrete, except when steel or wood piles are used.
In some building systems, the floor slab is designed to assist in carrying some of the lateral loads of the structure, and the floor slab thereby become an integral part of the framing system.