folk ballad vs folksong

folk ballad and folksong both are nouns.

Word	Noun	Adjective	Verb	Adverb
folk ballad	Yes	No	No	No
folksong	Yes	No	No	No

As nouns, folk ballad and folksong are synonyms defined as:

folk ballad and folksong: a song that is traditionally sung by the common people of a region and forms part of their culture

Other synonyms of folk ballad include folk song.

folk ballad (noun)	folksong (noun)
a song that is traditionally sung by the common people of a region and forms part of their culture	a song that is traditionally sung by the common people of a region and forms part of their culture