Abeir-Toril (or commonly referred to as Toril) is the name of the fictional planet that makes up the Forgotten Realms Dungeons & Dragons campaign setting, as well as the Al-Qadim and Maztica campaign settings and the 1st edition version of the Oriental Adventures campaign setting.
The name is archaic, meaning "cradle of life." It consists of various continents and islands, including Faerûn, Kara-Tur, Zakhara, Maztica, Osse, Anchorome and Katashaka, a sub-Saharan-like continent south of Maztica, where humanity appeared.
Toril was the name of Jeff Grubb's campaign world, and it was adopted as the name of the planet with the continent Faerûn when he and Ed Greenwood were designing the original Forgotten Realms Boxed Set in 1987. Abeir- was added as a prefix so that the world's name was placed at the beginning of an alphabetical encyclopedia.
Forgotten Realms material for the fourth edition of Dungeons & Dragons "reveals" that the world was split into two in prehistory, divided between the primordials (Abeir) and the gods (Toril). Toril is the world that has been showcased so far. A cataclysm called the Spellplague has caused several parts of the two worlds to switch places, displacing portions of Faerûn and the entire continent of Maztica with regions of Abeir: Tymanther, Akanûl and Returned Abeir.
It is orbited by one moon named Selûne, and by a cluster of asteroids, known as the Tears of Selûne.