space alien

space alien (plural space aliens)

1. (chiefly US) An extraterrestrial being; a visitor from outer space.
   • 1997, Janet Maslin, "Oh, Aliens: Business As Usual," New York Times, 1 Jul.:

     What would be the first question to ask a space alien newly arrived on planet Earth?

• In American usage, an extraterrestrial being is often called a "space alien," since the unqualified term "alien" is commonly used to denote a U.S. resident who is not a U.S. citizen.

• alien, ET, little green man

• space invader