Basically, you're talking about a style of hook. No different from a dry fly hook, wet fly hook or a streamer hook. If I slip a brass bead on a jig hook and tie a PT Nymph on it. I've tied a fly on that hook. If I tie a Clouser Minnow on a streamer hook using lead dumbbell eyes, I've tied a fly. If I slip a large brass bead or even use dumb bell eyes on a jig hook and tie the same pattern, have I tied a fly called the Clouser Minnow or a buck tail jig?