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.
Basement
Structurally, for houses, the basement walls typically form the foundation. In warmer climates, some houses do not have basements because they are not necessary (although many still prefer them). In colder climates, the foundation must be below the frost line. Unless constructed in very cold climates, the frost line is not so deep as to justify an entire level below the ground, although it is usually deep enough that a basement is the assumed standard. In places with oddly stratified soil substrata or high water tables, such as most of Texas, Oklahoma, Arkansas, and areas within of the Gulf of Mexico, basements are usually not financially feasible unless the building is a large apartment or commercial structure.