Beyond the history of particular words, I'm curious how people use them. (this is what I get for reading too much French Structuralism and post-structuralism
In the US*, I (strongly) suspect that there are multiple and competing definitions of both "martial art" and "budo." How they're associated with other terms (self defense, violence, mysticism, etc.) is important. Budo is probably scene as a subset of martial art.
In the US, I would bet Budo suggests a historical tie to Japan, and some vague notion of ideals beyond 'street effectiveness' (another vague notion for most). I'd be more curious to know how these words get used in Japan. Do the Japanese use Budo the same or different way that Americans do? I've heard Bujutsu, Budo, Bugei... what are other terms in Japanese for 'martial arts'?
Focusing on the origin of a term moves attention away from current usage and everything in between. This, IMHO, can be a problem if its done too much.
Sorry... I don't mean to threadcap, but this is a lil mini-rant I've been bottling up for about 2 years.
* I'm going to just be making stabs at my guesses on the US martial arts discourse (or whatever you want to call it). As I know nothing about any other country, I'm not going to even guess. I'm not assuming the US = the world