Foundation (engineering)
A foundation is the element of a structure which connects it to the ground, and transfers loads from the structure to the ground. Foundations are generally considered either shallow or deep. Foundation engineering is the application of soil mechanics and rock mechanics (Geotechnical engineering) in the design of foundation elements of structures.
Concrete slab
In many domestic and industrial buildings a thick concrete slab, supported on foundations or directly on the subsoil, is used to construct the ground floor of a building. These can either be "ground-bearing" or "suspended" slabs. The slab is "ground-bearing" if it rests directly on the foundation, otherwise the slab is "suspended". 
For double-storey or multi-storey buildings, the use of a few common types of concrete suspended slabs are used (for more types refer to the Concrete Slab#Design section below):