What does NETH stand for? 

neth

The planes of the Dungeons & Dragons roleplaying game constitute the multiverse in which the game takes place. Each plane is a universe with its own rules with regard to gravity, geography, magic and morality. There have been various official cosmologies over the course of the different editions of the game; these cosmologies describe the structure of the standard Dungeons & Dragons multiverse. The concept of the Inner, Ethereal, Prime Material, Astral, and Outer Planes was introduced in the earliest versions of Dungeons & Dragons; at the time there were only four Inner Planes and no set number of Outer Planes. This later evolved into what became known as the Great Wheel cosmology.: 86  The 4th Edition of the game shifted to the World Axis cosmology. The 5th Edition brought back a new version of the Great Wheel cosmology which includes aspects of World Axis model.In addition, some Dungeons & Dragons settings have cosmologies that are very different from the "standard" ones discussed here.: 95  For example, the Eberron setting has only thirteen planes, all of which are unique to Eberron.

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