folk song

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A song belonging to the folk music of a people or area, often existing in several versions or with regional variations.
• noun A song composed in the style of traditional folk music.

from The Century Dictionary.

• noun A song of the people; a song based on a legendary or historical event, or on some incident of common life, the words and generally the music of which have originated among the common people and are extensively used by them.
• noun A song written in imitation of the simple and artless style of such a popular song.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A song originating among the working people of urban and rural areas, and handed by oral tradition.
• noun A song in this style which may have been written in recent times.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a song that is traditionally sung by the common people of a region and forms part of their culture
• noun a song that is traditionally sung by the common people of a region and forms part of their culture