ANSWER
the word "astronaut" is made up of two root words:
"Astro" - which comes from the Greek word "astron" meaning star or celestial body. It is commonly used as a prefix to refer to things related to space or the stars.
"Naut" - which comes from the Greek word "nautes" meaning sailor or navigator. It is commonly used as a suffix to refer to someone who operates or navigates a vehicle or vessel.
Therefore, "astronaut" literally means "star sailor" or "navigator of the stars" and is a term used to refer to a person who travels or operates a spacecraft.