Weed Classification (Dank, Mids, Schwag)

Can somebody please explain to me the classification of dank, mids, and schwag? I know that that is in order of potency, but is potency the only thing that "classifies" your weed? Does it have anything to do with strain, how it is grown, part of the plant? For example, can a well-known strain, such as Haze, or White Widow, be considered mids or schwag? Thanks.

Swag is shit weed that gives u A headache, mids fall somewhere in the middle (obliously) and dank is what you wanna see in your bag.... And yes it's not just the strain it's also how if it was grown proberly (I.E got enough light, water and love)