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

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

• extraterrestrially adverb

Etymology

Origin of extraterrestrial

First recorded in 1865–70; extra- + terrestrial

Example Sentences

That kind of global spending sounds good but what about extraterrestrial spending?

From Barron's • Mar. 30, 2026

Because liquid water is essential for life as we know it, these moons rank among the most promising places in the solar system to search for extraterrestrial life.

From Science Daily • Mar. 2, 2026

“We do have some very anomalous objects,” he said, adding that the office, the All-domain Anomaly Resolution Office, hasn’t yet discovered verifiable evidence of extraterrestrial beings, activity or technology.

From The Wall Street Journal • Feb. 22, 2026

US President Donald Trump says he will direct US agencies, including the defence department, to "begin the process of identifying and releasing" government files on aliens and extraterrestrial life.

From BBC • Feb. 19, 2026

The Earth’s bacteria had infected the extraterrestrial invaders, who lacked immunity to them.

From "Spooked!" by Gail Jarrow