raft foundation vs foundation

raft foundation and foundation both are nouns.

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

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

raft foundation: a foundation (usually on soft ground) consisting of an extended layer of reinforced concrete
foundation: lowest support of a structure

Other hypernyms of raft foundation include base, foot, fundament, groundwork, substructure, understructure.

raft foundation (noun)	foundation (noun)
a foundation (usually on soft ground) consisting of an extended layer of reinforced concrete	the act of starting something for the first time; introducing something new
	lowest support of a structure
	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