Great Wheel is the cosmology model in which the world of Toril was said to exist during the first and second editions of the Advanced Dungeons & Dragons game, although the actual term "Great Wheel" didn't mean the cosmology as a whole until the 3rd edition of the D&D game and its Manual of the Planes 3rd edition. In second edition, "Great Wheel" or "Great Ring" meant the Outer planes only. The cosmology as a whole didn't require a name other than "the Planes" or "the Multiverse," as there weren't any formally named alternatives in the AD&D game.