social structure vs social system

social structure and social system both are nouns.

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

As nouns, social structure and social system are synonyms defined as:

social structure and social system: the people in a society considered as a system organized by a characteristic pattern of relationships

Other synonyms of social structure include social organisation, social organization, structure.

social structure (noun)	social system (noun)
the people in a society considered as a system organized by a characteristic pattern of relationships	the people in a society considered as a system organized by a characteristic pattern of relationships