"Once this was synonymous with 'folk' but no longer "
Yes it is Howard - this is how it was documented- if you pick a volume of songs from your shelf such as 'The New Penguin Book of Folk Songs" you will find a book full of traditional songs.
'The Gavin Greig Folk Song Collection' consists of 8 substantial volumes of traditional songs.
You can trace a continual thread of published folk songs from the beginning of the 20th century to the present day, all clearly defined as folk songs - a century and a quarter long pedigree.
Your man-in-the-street definition doesn't fit as a definition because it has no consensus - ask one man, you get one definition, ask another and you are quite likely to get a totally different one - not a definition, rather a series of 'Chinese whispers'.
The nearest the clubs come to a definition is either "what we (individual club) put on is folk" or "we don't need a definition" the music can range from High Baroque to heavy metal.
The definition has in no way changed - it has largely been totally abandoned by the clubs.
As Muskett said, if Fred Jordan walked into his club had be sat down and shown how it was done (this would include 'I Don't Like Mondays' presumably)
I'm coming around to thinking that Muskett's Anti-folk fundamentalism is why the club scene is where it is today.
I believe I'm better out of all this, but on the other hand, at one time the clubs provided a doorway into folk song for many thousands of people like me, who had no idea it existed - take them away and you close that doorway leaving no other access to a working peoples culture that has survived for many centuries.
Traditional music in Ireland will survive and develop for at least another two generations- English Traditional song has been left in the hands of a few 'tree-huggers' (as they were described by a university authority when it closed down its folk studies department).
That makes me both sad and angry enough to stand my ground.
Jim Carroll