Asked in The Hobbit and The Lord of the Rings
What's the world called in 'The Hobbit'?
The world of J.R.R. Tolkien in which his books The Hobbit and The Lord of the Rings are set is called Arda. Middle-earth is actually a continent in Arda, but the name has been used to refer to the whole fictional world. (IIRC, the world is not given a name in the actual Hobbit book itself, since Tolkien only integrated the Hobbit into his older Middle-earth world after he has already written it.)