contra danse vs folk dance

contra danse and folk dance both are nouns.

Word	Noun	Adjective	Verb	Adverb
contra danse	Yes	No	Yes	No
folk dance	Yes	No	Yes	No

As nouns, folk dance is a hypernym of contra danse; that is, folk dance is a word with a broader meaning than contra danse:

contra danse: a type of folk dance in which couples are arranged in sets or face one another in a line
folk dance: a style of dancing that originated among ordinary people (not in the royal courts)

Other hypernyms of contra danse include folk dancing.

contra danse (noun)	folk dance (noun)
a type of folk dance in which couples are arranged in sets or face one another in a line	a style of dancing that originated among ordinary people (not in the royal courts)

contra danse (verb)	folk dance (verb)
perform a contradance	perform a folk-dance