basis vs foundation

basis and foundation both are nouns.

Word	Noun	Adjective	Verb	Adverb
basis	Yes	No	No	No
foundation	Yes	No	No	No

As nouns, basis and foundation are synonyms defined as:

basis and foundation: the fundamental assumptions from which something is begun or developed or calculated or explained

Other synonyms of basis include base, cornerstone, fundament, groundwork.

As nouns, foundation is a hypernym of basis; that is, foundation is a word with a broader meaning than basis:

basis (noun)	foundation (noun)
the fundamental assumptions from which something is begun or developed or calculated or explained	the act of starting something for the first time; introducing something new
a relation that provides the foundation for something	lowest support of a structure
the most important or necessary part of something	a woman's undergarment worn to give shape to the contours of the body
	the fundamental assumptions from which something is begun or developed or calculated or explained
	education or instruction in the fundamentals of a field of knowledge
	an institution supported by an endowment
	the basis on which something is grounded