Hyperspace

In science fiction, hyperspace (subspace in Star Trek) refers to a region somehow alongside and connected with our own universe (in some cases displaced in the fifth dimension) which may be entered using some sort of energy field. Often spacecraft have some sort of drive capable of taking it into hyperspace, which has either different physical laws or a different geometry, allowing the craft to cross the universe at faster-than-light speeds and hence facilitating interstellar travel.