(astronomy, planets) A planet larger than terrestrial planets, composed mostly of gases and astronomical ices.

a terrestrial planet composed mostly of silicate minerals

(archaic) Afflicted by the astrological influence of a planet; struck down with amazement or shock; panic-stricken.

(astronomy, planetology) a planetary-mass object which has either been ejected from its system or was never gravitationally bound to any star or other such object, and that therefore orbits the galaxy directly.

(UK, slang) The Isle of Thanet.

Alternative form of Planet 9

(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

(astronomy) Any of the 8 celestial bodies which orbit the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune (a celestial body that fits the 2006 IAU definition of planet).

(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.