Wav, the definition of "folk song" is the 1954 definition.

Not all "folk song" is "trad" or "Anon" (eg "Fiddler's Green" clearly adopted into the community with alterations - likewise "Shoals of Herring" and probably "The Gay Fusilier", to exemplify 3 different composers/authors). Not all contemporary acoustic, even of folk-style, is "folk".