Inner Planes

The Inner Planes is a term from Dungeons & Dragons introduced in the Planescape setting. It is a way of collectively referring to the planes that make up the "center" of the Great Wheel cosmology; the Elemental Planes, the Energy Planes, the Astral Plane, the Ethereal Plane and (depending on who you're asking) the Prime Material Plane. By the admittedly biased beliefs of Sigilites, the Inner Planes are seen as, effectively, the boonies of the multiverse, being centered around more physical components than the more esoteric components of the Outer Planes, which are the realms of the dead and literally embodiments of the various moral alignments.