tribe vs folk

tribe and folk both are nouns.

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

As nouns, tribe and folk are synonyms defined as:

tribe (noun)	folk (noun)
a social division of (usually preliterate) people	the traditional and typically anonymous music that is an expression of the life of people in a community
a federation (as of American Indians)	people in general (often used in the plural)
group of people related by blood or marriage	a social division of (usually preliterate) people
(biology) a taxonomic category between a genus and a subfamily	people descended from a common ancestor