multiculturalism vs ism

multiculturalism and ism both are nouns.

Word	Noun	Adjective	Verb	Adverb
multiculturalism	Yes	No	No	No
ism	Yes	No	No	No

As nouns, ism is a hypernym of multiculturalism; that is, ism is a word with a broader meaning than multiculturalism:

multiculturalism: the doctrine that several different cultures (rather than one national culture) can coexist peacefully and equitably in a single country
ism: a belief (or system of beliefs) accepted as authoritative by some group or school

Other hypernyms of multiculturalism include doctrine, philosophical system, philosophy, school of thought.

multiculturalism (noun)	ism (noun)
the doctrine that several different cultures (rather than one national culture) can coexist peacefully and equitably in a single country	a belief (or system of beliefs) accepted as authoritative by some group or school