We've had this discussion before. For better or worse, the term "Celtic" has become established (at least in America) as a catch-all covering music based on the Irish, British Isles, and Atlantic Europe (read: Breton, Galician, etc.) musical traditions. Yes it's misleading, yes it's just plain wrong, yes it encompasses some of new age's worst excesses -- but it's here to stay, so we may as well get used to it.

Besides, it's much easier to say "I play Celtic music" than "I play music based on the Irish, British Isles, and Atlantic Europe (read: Breton, Galician, etc.) musical traditions."

Cheers,
Michael