What type of natural object is the Moon?

The Moon is a natural satellite.

A natural satellite is a celestial body that orbits a planet, dwarf planet, or other natural body rather than being built by humans. Earth’s Moon is the clearest example: it is a large, rocky object held in orbit by Earth’s gravity. “Moon” can also be used generically for natural satellites such as Jupiter’s Europa or Saturn’s Titan.

The term satellite originally referred to an attendant or companion. Johannes Kepler helped popularize its astronomical use in 1610, after Galileo discovered four moons orbiting Jupiter. That discovery showed that Earth was not the only planet with an orbiting companion. The Moon is not a comet, asteroid, or dwarf planet in this classification, although its planetary-scale size and geological history make it scientifically unusual among satellites.

Natural satellites differ from artificial satellites, which are human-made spacecraft. They can form from impacts, grow from material around a young planet, or be captured objects.