bloodline vs folk

bloodline and folk both are nouns.

Word	Noun	Adjective	Verb	Adverb
bloodline	Yes	No	No	No
folk	Yes	No	No	No

As nouns, folk is a hyponym of bloodline; that is, folk is a word with a more specific, narrower meaning than bloodline:

Other hyponyms of bloodline include family, family line, kinfolk, kinsfolk, phratry, sept, side, breed line.

bloodline (noun)	folk (noun)
ancestry of a purebred animal	the traditional and typically anonymous music that is an expression of the life of people in a community
the hereditary derivation of an individual	people in general (often used in the plural)
	a social division of (usually preliterate) people
	people descended from a common ancestor