There really is no difference. It's like calling a cougar a mountain lion. Same thing; just different names. It just has to do with the style in which you're playing.
Hey! yeah, the only diference is the style of playing, however if your realy serious... most fiddlers prefer a brighter sound rather than the more mellow. So steel strings or steel-gut. Also, you might look into getting a flatter bridge, since you'll prabably be playing alot of double stings, flat bridges are easyer than the rounded kind. but I dont have either, so dont stress-ou or any thing!lol.
I've been wanting to learn fiddle for along time now. I love the sound, and its almost a crime to be a southern musician and not play fiddle. Plus, my mama wants to relearn violin.