cosmonaut vs. astronaut

cosmonaut vs. astronaut: What's the difference?

Astronaut refers to a person engaged in or trained for spaceflight. Cosmonaut is the term used for a Russian or Soviet astronaut. Cosmonaut is a borrowing of the Russian word kosmonávt. Cosmo- comes from the Greek root kosmos-, meaning “universe,” while astro- comes from the Greek root astra- meaning “star.”