Astronaut (noun)

A person trained by a space agency to pilot or serve as a crew member of a spacecraft.

Origin:

Derived from the greek words 'astro' meaning 'star' and 'nautes' meaning 'sailor'.

Examples:

1. The first astronaut to walk on the moon was Neil Armstrong.
2. Astronauts undergo rigorous physical and mental training to prepare for their missions.
3. Astronauts must be able to function effectively in a high-stress, isolated environment.
4. The number of astronauts in the world is relatively small, and it is a highly competitive field.
5. Astronauts are considered heroes and role models, inspiring future generations to pursue careers in science and technology.