extraterrestrial

American  

[ek-struh-tuh-res-tree-uhl] / ˌɛk strə təˈrɛs tri əl /

adjective

1. outside, or originating outside, the limits of the earth.

   People on earth have long speculated about the idea of extraterrestrial life.

   Cataclysmic wildfires could be expected if earth were to take an extraterrestrial hit.

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noun

• extraterrestrials
  plural

1. a being originating from beyond the earth; an alien from outer space.

   It was your typical sci-fi novel about extraterrestrials conquering the earth.

extraterrestrial British  

/ ˌɛkstrətɪˈrɛstrɪəl /

adjective

1. occurring or existing beyond the earth's atmosphere

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noun

1. (in science fiction) a being from beyond the earth's atmosphere

extraterrestrial Scientific  

/ ĕk′strə-tə-rĕs′trē-əl /

1. Originating, located, or occurring outside the Earth or its atmosphere.

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extraterrestrial Cultural  

1. A descriptive term for things outside the Earth, such as possible civilizations outside the solar system, or objects, such as meteorites, that actually reach the Earth.

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Other Word Forms

Derived Forms

• extraterrestrially
  adverb

Inflected Forms

Nouns

• extraterrestrials
  plural

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Etymology

Origin of extraterrestrial

First recorded in 1865–70; extra- + terrestrial

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Explanation

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."

Example Sentences

See Examples For:

extraterrestrial extraterrestrials

As you roam the galleries, you’ll encounter many exhibits that aim to show the future of humankind’s extraterrestrial exploration.

From Los Angeles Times ● Oct. 28, 2026

Greg Olsen, the well-liked tight end whom Fox demoted to make way for handsome extraterrestrial Tom Brady, will be available at season’s end, and in high demand.

From The Wall Street Journal ● Oct. 20, 2026

Cramer has been going to conferences related to extraterrestrial matters for years, and he knows that his audiences have always been “outside the mainstream.”

From Slate ● Sep. 22, 2026

Shortly after the two major announcements of possible extraterrestrial life in 2025, we surveyed astrobiologists to understand how expert judgment was distributed across the field.

From Science Daily ● Sep. 9, 2026

An extraterrestrial civilization monitoring the radio emission from Earth and receiving such signals could not fail to conclude that something interesting had been happening here lately.

From "Cosmos" by Carl Sagan

Although there is speculation about the origins of the civilization—the notion that it might have been established by extraterrestrials remains widespread in China—experts’ understanding of how its people lived has grown, particularly after Ran’s discoveries.

From The Wall Street Journal ● Aug. 8, 2026

Diana Walsh Pasulka, a religion professor at the University of North Carolina Wilmington, said that for some, belief in extraterrestrials is akin to a kind of religion.

From The Wall Street Journal ● Jun. 18, 2026

In a follow-up post on Instagram, Obama, who served as US president between 2009-17, clarified: "I saw no evidence during my presidency that extraterrestrials have made contact with us. Really!"

From BBC ● Feb. 19, 2026

This one figures out how to converse with one of the deadliest extraterrestrials in the known universe — and not only does it understand her, it obeys her commands.

From Salon ● Sep. 24, 2025

She felt it was her responsibility to call as many homes as possible, warning that the extraterrestrials were on the way.

From "Spooked!" by Gail Jarrow

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