astronaut

noun

as·​tro·​naut ˈa-strə-ˌnȯt How to pronounce astronaut (audio)
-ˌnät
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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SpaceX’s Demo-2 test mission in 2020 marked the first launch of NASA astronauts from U.S. soil since the end of the Space Shuttle Program nine years earlier. Richard Tribou, The Orlando Sentinel, 23 July 2025 The idea of seriously designing an expedition to put astronauts on Mars has been kicking around for well over 70 years and is taken very seriously in certain quarters today. David Szondy july 21, New Atlas, 21 July 2025 The craft seemed ideal for welcoming travelers who were not former test pilots, as the earliest astronauts were—or who were not astronauts at all. Alice George, Smithsonian Magazine, 18 July 2025 Two Americans, one Japanese astronaut, and a Russian cosmonaut will ride to the station for a stay of at least six months. Stephen Clark, ArsTechnica, 16 July 2025 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 29 Jul. 2025.

Kids Definition

astronaut

noun
as·​tro·​naut ˈas-trə-ˌnȯt How to pronounce astronaut (audio)
-nät
: 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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