[ koz-muh-nawt, -not ]
/ ˈkɒz məˌnɔt, -ˌnɒt /


a Russian or Soviet astronaut.

Origin of cosmonaut

1955–60; cosmo- + (aero)naut, representing Russian kosmonávt

Related forms

cos·mo·nau·tic, adjectivecos·mo·nau·ti·cal·ly, adverb

Can be confused

astronaut cosmonaut Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for cosmonaut


/ (ˈkɒzməˌnɔːt) /


an astronaut, esp in the former Soviet Union

Word Origin for cosmonaut

C20: from Russian kosmonavt, from cosmo- + Greek nautēs sailor; compare Argonaut
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Culture definitions for cosmonaut


A crew member of a space mission launched by the former Soviet Union.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.