Among the Faith of the Seven, the seven wanderers are considered sacred, and each is equated with a god. The red wanderer, for instance, is sacred to the Smith. The seven wanderers are presumably other planets in the same solar system as the known world, given that the word "planet" means "wanderer".
Comets can also be referred to as wanderers.
A Clash of Kings
A Storm of Swords
Behind the Scenes
The English word "planet" comes from the Greek planḗtēs, meaning wanderer, referring to "wandering stars".