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

Etymology

Origin of extraterrestrial

First recorded in 1865–70; extra- + terrestrial

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

That’s right around the average success rate for all players over the past two decades, which means that the penalty spot is the one place where Messi goes from extraterrestrial to strangely mortal.

From The Wall Street Journal ● Jul. 8, 2026

For their argument, Schwitzgebel and Pober estimate that at least 1,000 behaviorally sophisticated extraterrestrial civilizations have existed somewhere in the universe.

From Science Daily ● Jun. 24, 2026

She prefers slumming it at extraterrestrial honky-tonks with suitors who look like armadillo-plated slugs.

From Los Angeles Times ● Jun. 24, 2026

With an ensemble cast led by Emily Blunt and Josh O'Connor, the action-packed Universal film follows an effort to reveal a decades-long coverup of extraterrestrial visitations.

From Barron's ● Jun. 21, 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

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

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

In the 1960s, an encounter with extraterrestrials leaves an interracial couple grappling with their experiences while a lesbian couple fashions their own love story in a time of queer repression.

From Los Angeles Times ● Sep. 2, 2025

If the extraterrestrials stay at home, there are at least two ways in which they might find out about us.

From "Cosmos" by Carl Sagan