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

Second, though “virtually all scientists” reject the idea that aliens have visited Earth, researchers are “increasingly confident that humanity will discover extraterrestrial life.”

From The Wall Street Journal ● Aug. 28, 2026

He’s not a super-scientist or a god or an extraterrestrial or a one-percenter able to develop all manner of nifty crime-fighting gadgetry.

From Los Angeles Times ● Aug. 4, 2026

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

That question is at the center of a new paper published in Nature Astronomy, where researchers examine the often-overlooked problem of "false negatives" in the search for extraterrestrial life.

From Science Daily ● Jun. 30, 2026

Charlie looks at Mom as if he’s afraid she’s about to turn into an extraterrestrial.

From "Marcus Vega Doesn't Speak Spanish" by Pablo Cartaya

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

Two Times staffers explore his ongoing fascination with extraterrestrials.

From Los Angeles Times ● Jun. 16, 2026

You can bet on Nepal’s elections, which actor will next play James Bond, the next cabinet member to exit the Trump administration, and even whether the U.S. will confirm before 2027 that extraterrestrials exist.

From The Wall Street Journal ● Mar. 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

A standard motif in science fiction and UFO literature assumes extraterrestrials roughly as capable as we.

From "Cosmos" by Carl Sagan