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

He held particular scorn for the flat-earthers, who he thought were plants to discredit genuine research about extraterrestrial technology.

From Slate ● Sep. 22, 2026

They didn’t indicate she was extraterrestrial in anyway.

From Los Angeles Times ● Sep. 14, 2026

In 2025, a press release stated that we have the “strongest hints yet” of extraterrestrial life on the exoplanet K2-18b.

From Science Daily ● Sep. 9, 2026

Popular belief in extraterrestrial life and alien encounters was one of the first markers of post-World War II psychology.

From The Wall Street Journal ● Aug. 28, 2026

“It’s Boy21 everywhere I go now. The time to leave Earth is soon. No point in lying about everything now. They’ve all seen my extraterrestrial powers anyway.”

From "Boy21" by Matthew Quick

The mysteries surrounding Sanxingdui have spawned even more outlandish questions: Do the enormous protruding eyes and enigmatic smiles featured on the figures suggest the ancient people were extraterrestrials?

From The Wall Street Journal ● Aug. 8, 2026

In the movie, Blunt plays Margaret Fairchild, a TV meteorologist chosen by extraterrestrials as the human through whom they communicate—“the last person on earth that you’d imagine would be destined for this task,” Blunt says.

From The Wall Street Journal ● Jun. 4, 2026

Inside its sci-fi trappings — space travel, crazy technology, oodles of extraterrestrials — Pixar’s “Elio” is the story of an outsider kid who finds a new family.

From Los Angeles Times ● Feb. 23, 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

God, angels, and extraterrestrials have yet to come to our assistance; yet more and more phenomena have proved explicable by the dim reason of human beings.

From "The Invention of Science" by David Wootton

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