astronaut

noun

plural astronauts
: a person whose profession is to travel beyond the earth's atmosphere
NASA on Wednesday introduced the group of astronauts it has chosen for upcoming missions to the moon. The program, called Artemis, aims to send people back to the moon for the first time since the end of NASA's Apollo program in 1972.Kenneth Chang
broadly : any person who travels beyond the earth's atmosphere
William Shatner, the 90-year-old actor of "Star Trek" fame, endured a 10-minute, rocket-powered ride to the edge of space … . In that moment, at least one thing became certain: Yes, a nonagenarian can be an astronaut. Jackie Wattles

Examples of astronaut in a Sentence

Recent Examples on the Web
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Starship and Blue Moon will both require refueling flights in order to land astronauts on the lunar surface and then launch them back to orbit around the moon to rendezvous with Orion. Josh Dinner, Space.com, 7 July 2026 Three of the astronauts, including Hansen, also made individual history. Eric Lagatta, USA Today, 8 July 2026 In 2017, Hansen became the first Canadian to lead a NASA astronaut class, training astronauts from the United States and Canada, according to the release. Matt Lavietes, NBC news, 7 July 2026 The mission forms part of NASA’s broader Moon-to-Mars strategy, gradually increasing operational complexity while preparing astronauts and technologies for eventual human missions to the Red Planet. Kaif Shaikh, Interesting Engineering, 7 July 2026 See All Example Sentences for astronaut

Word History

Etymology

astro- + -naut (in aeronaut)

Note: See note at astronautics.

First Known Use

1928, in the meaning defined above

Time Traveler
The first known use of astronaut was in 1928

Browse Nearby Words

Cite this Entry

“Astronaut.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/astronaut. Accessed 8 Jul. 2026.

Kids Definition

astronaut

noun
: a traveler in a spacecraft
astronautic
ˌas-trə-ˈnȯt-ik
adjective
or astronautical
-i-kəl
-nät-
Etymology

from astro- "star, heavens" (derived from Greek astron "star") and -naut (derived from Greek nautēs "sailor," from naus "ship") — related to nausea, nautical see Word History at nausea

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