(plural planetary objects)
- (astronomy) Any secondary body in the Solar system that is geologically differentiated or in hydrostatic equilibrium and thus has a planet-like geology: a planet, dwarf planet, or the larger moons and asteroids.
- (astronomy) Any substantial body in orbit around the Sun or other star: a planet, minor planet, or comet.
- (astronomy) Any substantial body associated with the development of planets: a protoplanet, planetesimal.
The phrase is often used for an unidentified body known to have complex geology, such as the unknown parent body of a meteorite.