extraterrestrial

Use the adjective extraterrestrial to describe anything that comes from or exists outside of the earth, like life on a distant planet, material from an asteroid, or even the sun.

The word extraterrestrial makes most people think of big-headed green aliens in spaceships, and if you saw one you'd be right to describe it that way. But as both a noun and an adjective, the word is most often used by scientists to talk about anything — life, rocks, or environments on other planets — that happens outside of the earth's atmosphere. This makes sense when you know that in Latin, extra means "outside" and terra means "earth."

Definitions of extraterrestrial
  1. adjective
    originating, located, or occurring outside Earth or its atmosphere
    “is there extraterrestrial life?”
  2. noun
    a form of life assumed to exist outside the Earth or its atmosphere
    synonyms: alien, extraterrestrial being
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    type of:
    hypothetical creature
    a creature that has not been observed but is hypothesized to exist
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