astronaut

American  

[as-truh-nawt, -not] / ˈæs trəˌnɔt, -ˌnɒt /

noun

• astronauts
  plural

1. a person engaged in or trained for spaceflight.

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astronaut British  

/ ˈæstrəˌnɔːt /

noun

1. a person trained for travelling in space See also cosmonaut

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astronaut Cultural  

1. A crew member of a space mission launched by the United States. (See Apollo program and Mercury program.)

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Other Word Forms

Noun Inflected Forms

• astronauts
  plural

Etymology

Origin of astronaut

1925–30; astro- + (aero)naut, probably via French astronaute; see astronautical

Compare meaning

How does astronaut compare to similar and commonly confused words? Explore the most common comparisons:

• cosmonaut vs. astronaut

Explanation

An astronaut is someone who travels in space. While the term was once reserved for military-trained professionals, recent accessibility of space travel has seen the term astronaut now used to refer to anyone traveling in a spacecraft, including civilians. The word astronaut includes the root naut, from nautes, the Greek word for "sailor." This suffix can be used to create many travel-specific words. For example, the Argonauts were mythical Greek sailors on the ship named the Argo. Astronaut gets the astro from the Greek word astron, meaning "star," making an astronaut a “star sailor.” Russian space explorers took the title cosmonauts, with the cosmo part coming from the Greek for "universe," kosmos, so both have the same meaning.

Example Sentences

See Examples For:

astronaut astronauts

On August 28, 2026, an astronaut aboard the International Space Station photographed the Saririaky anorthosite massif, a large body of rock exposed at Earth's surface.

From Science Daily ● Oct. 11, 2026

During the mission, Adenot became the first French female astronaut to venture outside the space station for a spacewalk.

From Barron's ● Oct. 8, 2026

The team is comprised of two Nasa astronauts, a Russian cosmonaut and a Canadian astronaut whose wife is expecting their third child two months into the mission.

From BBC ● Oct. 1, 2026

The unusual nature of the astronaut data helped researchers overcome some of that variability and strengthened confidence in the pattern they observed.

From Science Daily ● Sep. 28, 2026

After a week of testing, flight surgeon Robert Secrest told Jerrie that not only had she passed, but she had scored in the top 2 percent of all astronaut test candidates.

From "Women in Space" by Karen Bush Gibson

Standing alongside legendary astronauts like Neil Armstrong and Dick Gordon, a schoolboy from Lancashire was there to see the final manned lunar landing mission.

From BBC ● Oct. 11, 2026

Apollo astronauts returned samples of lunar anorthosite to Earth, giving researchers valuable material for studying the Moon's distant past.

From Science Daily ● Oct. 11, 2026

Finding accessible ice on the Moon could eventually allow astronauts to obtain water locally and potentially process it into oxygen and hydrogen for other uses.

From Science Daily ● Oct. 8, 2026

NASA’s Low Earth Orbit Program provides reliable access to space while maximizing research and development by partnering with private U.S. companies, including SpaceX, to transport astronauts to and from the International Space Station.

From Los Angeles Times ● Oct. 8, 2026

Only a handful of Soviet women had made spaceflights by 2012, whereas ten times as many American women had become astronauts and gone into space.

From "Women in Space" by Karen Bush Gibson

Related Words

• cosmonaut
• pilot