Another term for a terrestrial planet is a rocky planet. Terrestrial planets, including Mercury, Venus, Earth, and Mars, are characterized by their solid, rocky surfaces as opposed to gas giants like Jupiter and Saturn. These planets have varied geological features such as mountains, valleys, and craters, and their atmospheres are relatively thin, providing conditions for life on Earth. The study of terrestrial planets helps researchers understand planetary formation, geology, and the potential for life beyond our planet.