family line vs folk

family line and folk both are nouns.

Word	Noun	Adjective	Verb	Adverb
family line	Yes	No	No	No
folk	Yes	No	No	No

As nouns, family line and folk are synonyms defined as:

Other synonyms of family line include family, kinfolk, kinsfolk, phratry, sept.

family line (noun)	folk (noun)
people descended from a common ancestor	the traditional and typically anonymous music that is an expression of the life of people in a community
	people in general (often used in the plural)
	a social division of (usually preliterate) people
	people descended from a common ancestor