A non-place somewhere (e.g. between dimensions). Often characterized by lack of any planet or other large firmament, but contains small islands, or even artificial structures, floating in a starry ocean without sun or moon.
Alternate name: Aether
The first video game about Ether was released on November 27, 1993.
Often people traveling through dimensions end up in a place like this at some point in their travels as if it was a half-way station, the place between.