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

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Etymology

Origin of astronaut

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

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Compare meaning

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

• cosmonaut vs. astronaut

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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

An astronaut crew that carried out an eight-month mission aboard the International Space Station splashed down as planned Thursday off the coast of California.

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

Jeanette Epps, an astronaut aboard the International Space Station, Zoomed into my living room from 250 miles above Earth.

From Los Angeles Times ● Sep. 22, 2026

Even so, he does not expect Uhackatik to become an astronaut training site because reaching it is so difficult.

From Science Daily ● Sep. 22, 2026

Gene Nora Stumbough, a flying instructor at the University of Oklahoma, heard about the astronaut testing from Wally Funk at an Oklahoma college aviation gathering.

From "Women in Space" by Karen Bush Gibson

Along with everyday necessities for the astronauts, Dragon brought an unusual collection of scientific experiments that could help researchers develop new medical treatments and better understand how materials behave in space.

From Science Daily ● Oct. 16, 2026

Basalts collected by Chang'e-6 show chemical signatures indicating that they originated from depleted mantle material, much like the low-Ti basalts brought back by Apollo astronauts.

From Science Daily ● Oct. 14, 2026

Gethings was at the Space Center in Houston, Texas, when the astronauts on the moon's surface spoke directly to the group of students before collecting a moon rock from the surface.

From BBC ● Oct. 11, 2026

The crew also conducted nutrition-focused research and examined how physical characteristics may affect blood flow during spaceflight to help keep astronauts safe and healthy on future missions.

From Los Angeles Times ● Oct. 8, 2026

Some of them even exceeded the performance of the male astronauts.

From "Women in Space" by Karen Bush Gibson

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Related Words

• cosmonaut
• pilot

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