* Planets orbit the Sun: Planets are celestial bodies that orbit the Sun directly. The Moon orbits Earth, which in turn orbits the Sun.

* Planets are large and round: Planets have enough gravity to pull themselves into a nearly round shape. While the Moon is round, it's much smaller than any planet in our solar system.

* Planets have cleared their orbital path: Planets are dominant gravitational bodies in their orbital paths. They have cleared away most other objects from their orbit. The Moon shares its orbit with Earth.

In summary, the Moon is a satellite because it orbits a planet and doesn't meet the criteria for being a planet itself.