ex·​tra·​ter·​res·​tri·​al | \ ˌek-strə-tə-ˈre-strē-əl How to pronounce extraterrestrial (audio) , -ˈres-chəl, -ˈresh-chəl \

Definition of extraterrestrial

 (Entry 1 of 2)

: originating, existing, or occurring outside the earth or its atmosphere extraterrestrial life



Definition of extraterrestrial (Entry 2 of 2)

: a being from another world : an extraterrestrial being

Examples of extraterrestrial in a Sentence

Recent Examples on the Web: Adjective Known as Dragonfly, the mission will explore Saturn's largest moon, Titan, which could potentially host extraterrestrial life. Fox News, "NASA wants to use a steam-powered robot to explore icy moons that could host alien life," 29 June 2020 Europa, with an ocean hidden beneath a thick shell of ice, long has been viewed as a potential habitat for extraterrestrial life in our solar system, alongside other candidates such as Mars and Saturn’s moon Enceladus. NBC News, "Subsurface ocean on Jupiter's moon Europa was potentially 'habitable,' researchers say," 25 June 2020 Once tapped, this extraterrestrial reservoir could become the elixir of life to support human outposts, supplying not only drinking water but also oxygen and even rocket fuel. Leonard David, Scientific American, "NASA’s Hunt for Lunar Water Intensifies," 24 June 2020 But even if the Cold War did drive the two countries to compete for the first detection of extraterrestrial life, the search was a congenial endeavor. Nadia Drake, National Geographic, "My dad launched the quest to find alien intelligence. It changed astronomy.," 19 June 2020 During a press conference earlier in the week—held remotely due to rain—NASA Administrator Jim Bridenstine underscored the agency’s commitment to commercial spaceflight as a way to create a robust extraterrestrial economy. Daniel Oberhaus, Wired, "SpaceX Launched Two Astronauts—Changing Spaceflight Forever," 30 May 2020 The rover, which was recently renamed to Perseverance, will attempt to detect if there is any fossilized evidence of extraterrestrial beings, in addition to other tasks. Fox News, "NASA's next mission to Mars will honor those fighting against COVID-19," 18 June 2020 In the Drake equation, about half the unknowns are about extraterrestrial civilizations. Daniel Oberhaus, Wired, "The Trouble With Counting Aliens," 18 June 2020 The new research also suggests that searches for extraterrestrial intelligent civilizations not only reveals how life forms, but also gives us clues for how long our own civilization will last. Doyle Rice, USA TODAY, "We are not alone, study says: There could be 'dozens' of intelligent civilizations in our galaxy," 16 June 2020 Recent Examples on the Web: Noun Below his sweet words to his wife, Taylor, there’s a pair of the cartoonist’s trademark blue extraterrestrials. Byangela Haupt, Washington Post, "How 12 authors turned their book dedications into grand romantic gestures," 11 Feb. 2020 Another thing that enterprising extraterrestrials might do is simply monitor the total amount of light coming from Earth — even seen in a single pixel. NBC News, "We keep looking for space aliens. Are they looking for us?," 18 Sep. 2019 Sharon Wehrly, the sheriff in adjacent Nye County, home to the Area 51 Alien Center, said messages discouraging Earthlings from trying to find extraterrestrials in Amargosa Valley appeared to work. Travis Fedschun, Fox News, "'Storm Area 51' raid brings alien 'community of believers' to Nevada desert," 20 Sep. 2019 In a section about smoking a spliff on the balcony, a friend’s pointed question about Pico’s ex turns into a far-out conversation about extraterrestrials, as though the poem were getting stoned as well. Dan Chiasson, The New Yorker, "Tommy Pico Filibusters Mortality with Poetry," 6 Jan. 2020 Based on a Ray Bradbury short story about an astronomer’s encounter with extraterrestrials in the Arizona desert. Los Angeles Times, "Movies on TV this week: Sunday, Sept. 22, 2019," 22 Sep. 2019 After all, if extraterrestrials are unaware of our world and its properties, what would spur them to transmit signals in our direction? NBC News, "We keep looking for space aliens. Are they looking for us?," 18 Sep. 2019 Kean is convinced that there are unexplained aerial phenomena, but not convinced its extraterrestrials. Matt Blitz, Popular Mechanics, "Angels, Airships, and Aliens: The 3,500-Year History of UFO Sightings," 24 Sep. 2019 Nothing is known about how extraterrestrials might take in information. The Economist, "How to talk to aliens," 28 Nov. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'extraterrestrial.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of extraterrestrial


1848, in the meaning defined above


1950, in the meaning defined above

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The first known use of extraterrestrial was in 1848

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Last Updated

5 Jul 2020

Cite this Entry

“Extraterrestrial.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/extraterrestrial. Accessed 15 Jul. 2020.

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More Definitions for extraterrestrial


How to pronounce extraterrestrial (audio)

English Language Learners Definition of extraterrestrial

: coming from or existing outside the planet Earth

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Spanish Central: Translation of extraterrestrial

Nglish: Translation of extraterrestrial for Spanish Speakers

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