Satellite

Synonym: moon (lowercase "m", not to be confused with the "Moon").

A celestial body orbiting a planet.

Astronomy

In our solar system Mercury and Venus are the only planets to have no satellites.

• The only satellite of the Earth is the Moon.
• Mars has two satellites: Phobos and Deimos.
• Jupiter, Saturn, Uranus and Neptune have several satellites; the biggest known satellite of our solar system is Titan, a satellite of Saturn.
• Pluto, Haumea and Eris are the only dwarf planets to have satellites; Charon is the only known satellite of Pluto: Charon is so big relative to Pluto that this couple is going to be considered a "binary (dwarf) planet" rather than a (dwarf) planet with its satellite, though this is not an official definition yet.

Astrology

The only satellite to have astrological relevance is the Moon; this because the perspective of astrology is the Earth and the Moon is its only satellite. Being a "wandering star", the Moon is counted as a planet in astrological terminology.

The other satellites of our solar system are all very near to the planet they orbit, as they are seen from the Earth; therefore they usually have no relevance in astrology.