foam vs suds

foam and suds both are nouns.

Word	Noun	Adjective	Verb	Adverb
foam	Yes	No	Yes	No
suds	Yes	No	Yes	No

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

Other hyponyms of foam include shaving foam, head, lather, lather, soapsuds, spume, white water, whitewater.

foam (noun)	suds (noun)
a mass of small bubbles formed in or on a liquid	a dysphemism for beer (especially for lager that effervesces)
a lightweight material in cellular form; made by introducing gas bubbles during manufacture	the froth produced by soaps or detergents

foam (verb)	suds (verb)
become bubbly or frothy or foaming	make froth or foam and become bubbly
	wash in suds