astronaut
n. countablen. a person who is trained to travel and work in a spacecraft. They often live on a space station to do scientific experiments.
n. a person trained by a human spaceflight program to command, pilot, or serve as a crew member of a spacecraft.
The astronaut floats inside the space station.
After years of intense physical and mental training, she finally became an astronaut for the national space agency.
Modern astronauts must possess not only technical engineering skills but also the psychological resilience required for long-duration missions in the confined environment of a lunar base.
From astro- + -naut. Coined from Ancient Greek ἄστρον (ástron, “star”) and ναύτης (naútēs, “sailor”).
Typically refers to travelers from Western space programs; 'cosmonaut' is the specific term for those from the Russian program.