subsidy vs subvention

subsidy and subvention both are nouns.

Word	Noun	Adjective	Verb	Adverb
subsidy	Yes	No	No	No
subvention	Yes	No	Yes	No

As nouns, subvention is a hyponym of subsidy; that is, subvention is a word with a more specific, narrower meaning than subsidy:

subsidy: a grant paid by a government to an enterprise that benefits the public
subvention: grant of financial aid as from a government to an educational institution

Other hyponyms of subsidy include price support.

subsidy (noun)	subvention (noun)
a grant paid by a government to an enterprise that benefits the public	the act or process of providing aid or help of any sort
	grant of financial aid as from a government to an educational institution

subsidy (verb)	subvention (verb)
	guarantee financial support of