I have a collection of planets around a sun in my game, and each planet can have a set of moons. I'd like to know how to call such a single planet and moons system.

This is in distinction to all the satellites (and their satellites) around a star. I am asking about how to refer to a single planet and its moons.

  • If this is for a game and the playable area or "known area" in-game is confined to the planet and its moons, you could just call it something sort of broad like the reach.
    – Adam
    Jun 12, 2016 at 7:41
  • There's this double-planet system that once unofficially referred to the Earth-Moon system.
    – NVZ
    Jun 12, 2016 at 7:56
  • Maybe useful, it relates to gravity wells - en.wikipedia.org/wiki/Sphere_of_influence_(astrodynamics) and en.wikipedia.org/wiki/Hill_sphere
    – Phil Sweet
    Jun 13, 2016 at 15:48
  • It's funny there's a term for all the planets and their satellites "Planetary system" and a term for only all the stuff orbiting around one planet "satellite system" but none for one planet and it's satellite system. I guess you have to use Planet xxx system.
    – P. O.
    Jun 13, 2016 at 16:05
  • Just call it a planet. It should be understood that planets have zero or more moons.
    – dangph
    Jun 14, 2016 at 5:07

3 Answers 3


How about just planet region?

Consider this:

We're now passing through the Jupiter region with its remarkable satellites.

The region would suggest it's a planet and a little extra. Since planet's satellites are orders of magnitude closer to the planet than any other celestial objects, it is safe to assume they belong to the region implicitly.

  • I think in the context of my game, region is going to make the most sense. Thank you. Jun 14, 2016 at 5:00

If the planet has a name, then (the adjectival form of) the planet's name followed by system seems common in both SF and real usage.

For example the Martian system comprises Mars, Phobos and Deimos. The phrase is widely used online.

Earth system doesn't appear to be widely used in this context. Earth-moon system is used in some discussions while the use of Terran system seems to be confined (almost) to SF.


See planetary system at Wikipedia.

A planetary system is a set of gravitationally bound non-stellar objects in orbit around a star or star system.

Go here at space/stackexchange and have a look.

  • 4
    So that would be all the planets and their moons, not a single one.
    – Mr Lister
    Jun 12, 2016 at 8:19
  • Right, I'm just looking for a single planet and its moons. Jun 12, 2016 at 8:19
  • I'm still looking for it.
    – vickyace
    Jun 12, 2016 at 8:23
  • 1
    I thought the answer was "planetary system" before I saw that wikipedia page. You could call it the Planetname subsystem. Jun 13, 2016 at 15:25

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