Search the Dictionary:

 
A-B-C-D-E-F-G-H-I-J-K-L-M-N-O-P-Q-R-S-T-U-V-W-X-Y-Z
 
astronaut
Astronaut Piers Sellers during the third spacewalk of STS-121, a demonstration of orbiter heat shield repair techniques. Credit: NASA, Astronaut Michael Edward Fossum.

astronaut:

A person who has studied astronautics, the science of space flight, and has been especially trained to fly in space. [Astronaut comes from Greek words meaning “star sailor.”]