Party of Scoundrels
It is called such because oral tradition says the world once consisted of a supercontinent with the lands now known as Faerun at it’s center, until it was divided by the god Ao. It is known.
Forgotten Faerun, the all encompassing universe as we know it on our material plane. The “known” world is Toril, which contains the continent of Faerun and a few other commonly known continents, like Kara-Tur. Other areas such as the Far East, The Hordelands, & the Underdark are at least known to commoners by name, if they know nothing else.
Of course, there are many other continents in the uncharted waters of Toril. For example, to the west of the Trackless Sea you can find the continent that holds the pirate haven & smuggling capital of the world, Sasserine.
Possibly undiscovered continents include the land of Greyhawk, the continent of Khorvaire in the land of Ebberon, and commoners whisper legends of Dragonlance, a land where dragons are as common as people on a continent called Krynn.