folk vs ethnic music

folk and ethnic music both are nouns.

Word	Noun	Adjective	Verb	Adverb
folk	Yes	No	No	No
ethnic music	Yes	No	No	No

As nouns, folk and ethnic music are synonyms defined as:

folk and ethnic music: the traditional and typically anonymous music that is an expression of the life of people in a community

Other synonyms of folk include folk music.

folk (noun)	ethnic music (noun)
the traditional and typically anonymous music that is an expression of the life of people in a community	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