Lower Planes
The Lower Planes is a term from Dungeons & Dragons introduced in the Planescape setting. It is a way of collectively referring to the five planes that are characterized by their prominent Evil alignment; the Nine Hells of Baator, Gehenna, Hades, Carceri and the Abyss, as on the standard planar "map" these make up the lower half of the Great Wheel.
The Lower Planes are, of course, contrasted by the Upper Planes and the Middle Planes, which collectively make up the Outer Planes.