A shuffle is a word to desribe a basic rhythm on the fiddle. The most common rhythms (in Ameircan and British fiddling, anyway) are
1) the simple shuffle, which is played with one lonng note and two short ones, the rhythm comes out as bumtitty bumtitty etc.
2) Sawmill, chatanooga or alligator bowing. This just involves one bow struck per note, the words alligator or chatanooga repeated fast give you the rhythm you are aiming at. These shuffles are the basis of folk fiddling(though accomplished fidders can get waway from using them much, in all sorts of ways). But these are definitely the first things to learn if you want to be a fiddler. Just put your bow on the D and A string together aand try either of these rhyhms . Have fun. When you're trying the chaatanooga one, play a don bow first, and just go up and down. All the main beats will be down bows. When doing the bumtitty rhythm (the "simple shuffle" or just "the shuffle"), if you start on a down bow, you'll find the next dtrong beat(on "bum") will be an up-bow. They alternate, which seems awkard, but plug away till youve got this rhyhtm. That is what people will dance all night to!