astronaut

noun

as·​tro·​naut ˈa-strə-ˌnȯt 

-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

Word Icons

Examples of astronaut in a Sentence

Recent Examples on the Web

Just as the cost of computer processing has plummeted since the first mainframes — with smartphones now packing more computing power than the machines that sent astronauts to the moon — there has always been reason to believe AI’s massive energy appetite would come down. —Jackie Snow, Quartz, 3 Feb. 2025

Muscle atrophy is a common ailment that astronauts must face off, although drugs have been shown to lessen its effects, and recent research has found that microgravity can also damage astronauts' eyesight. —Keith Cooper, Space.com, 3 Feb. 2025

Spending time in each astronaut’s head is a sparkling gift. —Barbara Ellis, The Denver Post, 3 Feb. 2025

And the filmmaker follows up his dismissiveness with sitcom and movie clips making jabs at the notion of female astronauts. —Lisa Kennedy, Variety, 3 Feb. 2025

Word History

Etymology

astro- + -naut (in aeronaut)

Note: See note at astronautics.

First Known Use

1928, in the meaning defined above

Kids Definition

astronaut

noun

as·​tro·​naut ˈas-trə-ˌnȯt 

-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