Pop music is a shortening of popular music. if 51% of the public listened to folk music more than any other type, would we have to start calling it pop music? That's the logical conclusion of some of the posts up there...

Prof Child famously called his collection Popular Ballads; it's exactly the same usage that's in Popular=Pop Music. I have books on Popular Art that some would now call Folk Art. Popular as in People not Popular as in Numbers. Pop and Folk - the words are synonymous, yet Folk is driven by a wonky agenda by which some might say otherwise, which is a bit of a shame really but each to their own.