I've always considered a snap cut to be when you are chunking out pieces of wood by cutting perpendicular and/or on both sides of the limb slightly overlapping the cuts. Then you put your saw away, and with a little wiggle or push with the hand, it snaps off, hence the name snap cut. That only works on pieces that you can handle, but it allows you to throw the piece any where you want. Otherwise if I'm just dropping a limb I make an undercut, then the top cut a couple inches out. If it's a big limb, then I make the top cut directly over the undercut so the bar doesn't get caught in the kerf, (which I've seen a guy loose his saw that way). I never really considered cutting it that way to have a name, just that's the way you do it, so you don't peel off the bottom. I always thought if you reverse the cuts, make a undercut then make the top cut a couple inches in, it was considered a jump cut but I've never messed with that, so I'm not sure about the jump cut stuff. Then there is the hinge cut where you just slowly make a top cut. That's how I've always interpet it, and only called a snap cut where you snap the branch with two perpendicular cuts. I'm not saying I'm right, I'm just saying that's how I've always made my cuts (depending on branch size, type of tree, etc, etc.) and how I've called it.