Indeed, Steve. However there are problems with 'source singer' as well, in that (a) some enthusiasts for traditional song feel that it reduces singers to mere repositories of repertoire, rather than actual people, and (b) I've already seen the argument advanced in this forum that anyone whose song is learned by another person is by definition a 'source singer'. Seems to me some folk don't like any kind of definitions at all. But however much we pull apart terms like 'folk', 'traditional' or 'source', in the end we still need some way of differentiating Kate Rusby from Queen Caroline Hughes (names chosen at random and non-judgementally) if we're going to discuss the performance of traditional song.