I really don't want to get back to these nit-picking arguments about definitions. What about custom and usage? We've had these discussions over and over and over. The English language, like many another, is very fluid. Dictionaries sometimes struggle to keep up with usage. I am not an academic, I'm a writer/researcher, and to be absolutely honest I'd rather listen to the word on the street than pick up a dictionary or accept the word of some academic who has to toe the line. The various meanings of 'folk' are well-known in the circles I inhabit and I'm quite aware of the broad meaning Joe Public uses. We are talking about words that millions of people use every day. They don't all use the word in quite the same way but there has to be some concensus or total confusion would ensue.