cosmonaut: A cosmonaut is a person from Russia who is trained to travel in space. The word "cosmonaut" has the same meaning as the word "astronaut." In Russia, the term cosmonaut is used, while in the U.S.A., space travelers are called astronauts.
crater: When a planet or a moon is struck by a meteorite, the impact throws rock and soil away from the area around the point of impact. The result is a round, bowl-shaped hollow called a crater. The size of the crater depends on the mass of the meteorite that caused it.
