social unit vs family

social unit and family both are nouns.

Word	Noun	Adjective	Verb	Adverb
social unit	Yes	No	No	No
family	Yes	No	No	No

As nouns, family is a hyponym of social unit; that is, family is a word with a more specific, narrower meaning than social unit:

social unit (noun)	family (noun)
an organization regarded as part of a larger social group	primary social group; parents and children
	people descended from a common ancestor
	a social unit living together
	(biology) a taxonomic group containing one or more genera
	a collection of things sharing a common attribute
	an association of people who share common beliefs or activities
	a loose affiliation of gangsters in charge of organized criminal activities
	a person having kinship with another or others