"Let us commence with the folk song, which, although it cannot be included in the category of absolute music, because it is associated with words, has a very definite musical design. This design embodies the principle of simple repetition such as we find in textiles and wall papers, with the fundamental difference, however, that folk songs have a definite beginning and ending. Wall papers more closely resemble the primitive designs of savages in which a single musical phrase is repeated indefinitely.
Folk songs are short musical settings of popular verse. They are often of uncertain origin."
[ from: Douglas Moore, 'Listening to Music' - Norton & Company, New York (1932 / 1964) ]