(astronomy) A theoretical ninth planet in the Solar system, the gravitational effects of which would explain the improbable orbital configuration of a group of trans-Neptunian objects that orbit mostly beyond the Kuiper belt.

Alternative form of Planet 9

plural of rogue planet

(planetology) a planet that flies through interstellar space and has no star to encircle

(science fiction) homeworld

plural of classical planet

plural of diamond planet

(astronomy) Synonym of carbon planet

(astrology, astronomy) The seven non-fixed astronomical objects in the sky visible to the naked eye that where known in Ancient history

(astrology) A planet thought to bring bad luck to those born within its radius