Wiktionary
a. 1 (context jargon science fiction English) Originating outside the known physical reality of the universe. 2 (context jargon science fiction English) Coming from a dimension outside Einsteinian space-time.
Usage examples of "extradimensional".
He moved through, circumventing the material distance to the ravine's floor with a single extradimensional step.
The two powerful beasts followed Aballister out of the room and out of another door in the extradimensional mansion that led to the rocky ridge above Castle Trinity, where Dorigen, her crystal ball in hand, waited.
Then the besieged extradimensional entity began to physically shrink in size, its tendrils retracting and diminishing until all that was left was a tiny wriggling creature about the size of a small jellyfish.
Temok, because changelets are extradimensional, they are extraordinarily massive when compared with other subatomic particles.