This article is about the celestial body. For a list of moons, see Category: Moons. For the action of displaying one's buttocks for shock value, find a different encyclopedia, you pervert.
A moon is a celestial body that orbits a planet as a natural satellite. A planet may have any number of moons, ranging from none to five thousand. Inhabitants of a planet with only one moon generally refer to it with their language's equivalent of "the moon" and don't get around to officially naming it for a while. The gravitational pull of a moon usually creates tidal forces in whatever bodies of water the planet happens to have, and the light it reflects from the sun usually gives it a glow that is perfect for romantic moments and howling nocturnal animals.
Moons are constructed for sale by skilled artisans in the Farflux Dimension. Of course, one could just ask the Magratheans for a planet and have them scale it down a bit, but that wouldn't be nearly as fun.