Void

A term used by Tolkien in various ways, but that in general seems to describe the uninhabited regions of the universe. In particular, the Void is that part of existence outside the World, but the Timeless Halls of Ilúvatar seem to be apart from the Void, too. After his defeat in the War of Wrath, Melkor was cast out into the Void, but legends predict that he will return to the World before its end.