interstellar planet

Constructed from Latin: inter- +‎ stellar +‎ planet. The latter derives from Middle English planete, from Old English planēta (“planet, chasuble”), from Latin planeta, planetes, from Ancient Greek πλανήτης (planḗtēs) variant of πλάνης (plánēs, “wanderer, planet”), from πλανάω (planáō, “wander about, stray”), of unknown origin. Perhaps from a Proto-Indo-European *pel- (“to wander, roam”), cognate with Latin pālor (“wander about, stray”), Old Norse flana (“to rush about”), Norwegian flanta (“to wander about”). More at flaunt.

interstellar planet (plural interstellar planets)

1. (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.

• free-floating planet
• nomad planet
• orphan planet
• rogue planet

• exocomet
• exoplanet
• exosolar planet
• extrasolar planet
• interstellar comet

• deep space
• outer space
• planetary system