n. 1 a the solid ground or base, natural or artificial, on which a building rests. b (usu. in pl.) the lowest load-bearing part of a building, usu. below ground level. 2 a body or ground on which other parts are overlaid. 3 a basis or underlying principle; groundwork (the report has no foundation). 4 a the act or an instance of establishing or constituting (esp. an endowed institution) on a permanent basis. b such an institution, e.g. a monastery, college, or hospital. 5 (in full foundation garment) a woman's supporting undergarment, e.g. a corset. foundation cream a cream used as a base for applying cosmetics. foundation-stone 1 a stone laid with ceremony to celebrate the founding of a building. 2 the main ground or basis of something. foundational adj.
[ ME f. OF fondation f. L fundatio -onis (as FOUND(2)) ]