"I do not think a definition of "folk music and song" is possible"
Too late - it's been done and written up
If it hadn't been possible we wouldn't be here talking to each other
You don't really need a set definition - you can tell by the sound of the songs that they are something special

Oh has it ~ by whom?? the term Folk was initially a term for songs and music ~ "from the people by the people" and really evolved with story telling to tell a story ~ the tunes of course helping memory and the conveying of that story

People are people (folk is folk) and all have their own ideas and definitions ~ "already defined" oh yes when where and what gives them that right prithee?

Something special does not necessarily equate with "folk"

Ray