The document defines basic vocabulary related to the Solar System, including terms like universe, galaxy, Milky Way, Solar System, Sun, planets which are divided into inner planets like Mercury, Venus, Earth, Mars and outer planets like Jupiter, Saturn, Uranus, Neptune. It also mentions dwarf planets like Pluto and other celestial bodies such as comets, asteroids, and satellites, and describes their rotational and translational movements as well as elliptical orbits around the Sun.