cosmonaut

noun

cos·​mo·​naut ˈkäz-mə-ˌnȯt How to pronounce cosmonaut (audio)
-ˌnät
: an astronaut of the Soviet or Russian space program

Examples of cosmonaut in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Roscomos cosmonaut Aleksandr Gorbunov making his first flight. Richard Tribou, The Orlando Sentinel, 30 Mar. 2026 Soviet cosmonaut Yuri Gagarin had become the first human to voyage into space just a month before, with American astronaut Alan Shepard close on his heels. Sarah D. Wire, USA Today, 23 Mar. 2026 Here we’re offered what's sure to be a fascinating glimpse into the complex lives and loves of cosmonauts, scientists, engineers, researchers, intelligence leaders, and espionage agents working within the Soviet space program and their sacrifices made for the benefit of Earth. Jeff Spry, Space.com, 27 Feb. 2026 Johnson’s figures later enabled the U.S. to answer the Soviets’ April 1961 Vostok 1 flight, which made cosmonaut Yuri Gagarin both the first man in space and the first to orbit the planet. Nicole Briese, PEOPLE, 19 Jan. 2026 See All Example Sentences for cosmonaut

Word History

Etymology

Russian kosmonavt, from Greek kosmos + Russian -navt (as in aeronavt aeronaut)

First Known Use

1955, in the meaning defined above

Time Traveler
The first known use of cosmonaut was in 1955

Browse Nearby Words

Cite this Entry

“Cosmonaut.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/cosmonaut. Accessed 6 Apr. 2026.

Kids Definition

cosmonaut

noun
cos·​mo·​naut ˈkäz-mə-ˌnȯt How to pronounce cosmonaut (audio)
-ˌnät
: a Soviet or Russian astronaut

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