Planetary systems refer to groups of celestial bodies that orbit a star or stars. There are a range of synonyms for planetary systems, including solar systems, stellar systems, star systems, and galactic systems. Some other terms that can be used to describe planetary systems include exoplanetary systems, extrasolar systems, and multiplanetary systems. These terms are used to describe the, often complex, arrangements of planets, dwarf planets, moons, asteroids, and comets that orbit stars. The study of planetary systems is known as planetary science and this field of study is essential in helping us understand our place in the cosmos and the potential for finding life beyond our planet.