- Extraterrestrial is defined as something from space.
An example of extraterrestiral would be intelligent life forms that come from another planet.
- The definition of an extraterrestrial is an alien, or a hypothetical or fantasy figure of some intelligent being that lives on a planet other than earth.
An example of an extraterrestrial is the alien E.T. from the movie or Alf from the TV show.
One persons idea of an extraterrestrial.
(comparative more extraterrestrial, superlative most extraterrestrial)
extra- + terrestrial