BSL Astronomy Glossary - moon(s) - definition
Definition: The term moon refers to any natural object that orbits a planet, including our own Moon that orbits Earth. In the same way that the planets in our solar system orbit around the sun, moons orbit around individual planets. Examples of other moons include those which orbit Mars and Earth. Moons are distinct from other, man-made objects that can orbit planets, such as space stations, because they are always naturally occurring objects.