Gap Between Dimensions

The Gap Between Dimensions is a location mentioned in The Legend of Zelda: Ocarina of Time. After Link defeats Phantom Ganon in battle, Ganondorf banishes the phantom to the gap, calling him a "worthless creation".

It is unknown what exactly the Gap Between Dimensions is, but it can reasonably be anything from an empty void, to the Twilight Realm, to the use of creative license.