pluralism vs social system

pluralism and social system both are nouns.

Word	Noun	Adjective	Verb	Adverb
pluralism	Yes	No	No	No
social system	Yes	No	No	No

As nouns, social system is a hypernym of pluralism; that is, social system is a word with a broader meaning than pluralism:

pluralism: a social organization in which diversity of racial or religious or ethnic or cultural groups is tolerated
social system: the people in a society considered as a system organized by a characteristic pattern of relationships

Other hypernyms of pluralism include social organisation, social organization, social structure, structure.

pluralism (noun)	social system (noun)
the practice of one person holding more than one benefice at a time	the people in a society considered as a system organized by a characteristic pattern of relationships
the doctrine that reality consists of several basic substances or elements
a social organization in which diversity of racial or religious or ethnic or cultural groups is tolerated