intergalactic

/ˌˈɪntərgəˌlæktɪk/

The adjective intergalactic describes something that's in between galaxies. An intergalactic star, for example, is not inside a galaxy, but between them — it's also called a "rogue star."

You can call anything that relates to galaxies, or exists between them, intergalactic. If we were able to travel at the speed of light, intergalactic travel — travel from one galaxy to another — might be possible. The prefix inter- means "between" or "among," and it's followed by galactic, "pertaining to our galaxy," from the Late Latin root galaxias, "the Milky Way."

Definitions of intergalactic

1. adjective

   between or among galaxies
   “intergalactic space”