extraterrestrial

1 of 2

adjective

ex·​tra·​ter·​res·​tri·​al ˌek-strə-tə-ˈre-strē-əl How to pronounce extraterrestrial (audio)
-ˈres-chəl,
-ˈresh-chəl
: originating, existing, or occurring outside the earth or its atmosphere
extraterrestrial life

extraterrestrial

2 of 2

noun

: a being from another world : an extraterrestrial being

Examples of extraterrestrial in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Adjective
If future observations detect telltale radio emissions from 3I/ATLAS, the finding could become a pivotal moment in the search for extraterrestrial intelligence. Jordan King, MSNBC Newsweek, 8 Oct. 2025 Enceladus, a small moon harboring a vast ocean beneath its icy surface, has long been considered one of our solar system's best places to search for conditions suitable for extraterrestrial life – and perhaps, even life itself. Eric Lagatta, USA Today, 3 Oct. 2025
Noun
From microbial fossils on Mars to interstellar comets to mysterious signals in deep space, there is a timeless curiosity around extraterrestrials. Kenna Hughes-Castleberry, Space.com, 7 Oct. 2025 Loeb has long had a preoccupation with extraterrestrials – even co-founding the Galileo Project, a research program at the Harvard-Smithsonian Center for Astrophysics dedicated to the search for alien life. Eric Lagatta, USA Today, 2 Oct. 2025 See All Example Sentences for extraterrestrial

Word History

First Known Use

Adjective

1848, in the meaning defined above

Noun

1950, in the meaning defined above

Time Traveler
The first known use of extraterrestrial was in 1848

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Cite this Entry

“Extraterrestrial.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/extraterrestrial. Accessed 15 Oct. 2025.

Kids Definition

extraterrestrial

adjective
ex·​tra·​ter·​res·​tri·​al
ˌek-strə-tə-ˈres-trē-əl
: coming from or existing outside the earth or its atmosphere
extraterrestrial life
extraterrestrial noun

More from Merriam-Webster on extraterrestrial

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