- The definition of an astronaut is a person who either travels into space or who is trained to travel into space.
An example of an astronaut is Neil Armstrong, the man who walked on the moon.
An astronaut floating in space.
Origin of astronaut; from French astronaute: see astro- and amp; aeronaut
Origin of astronautastro– + Greek nautēs, sailor (from naus, ship; see nāu- in Indo-European roots).
Coined from Ancient Greek ἄστρον (ástron, “star”) and ναύτης (naútēs, “sailor”).