- 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.
astronaut definition by Webster's New World
Origin: ; from French astronaute: see astro- and amp; aeronaut
astronaut definition by American Heritage Dictionary
Origin: astro- + Greek nautēs, sailor (from naus, ship; see nāu- in Indo-European roots).
astronaut - Cultural Definition
A crew member of a space mission launched by the United States. (See Apollo program and Mercury program.)