Protoplanet

noun

noun ·Rare ·Advanced level

Definitions

Noun
  1. 1
    An astronomical object, approximately the size of the Moon, formed from the mutual gravitational attraction of planetesimals; they are thought to collide with each other and slowly form planets

    "Tyrix, one of the largest objects in Thal's asteroid belt, is a metallic asteroid with an iron-nickel core under a rocky olivine mantle. It is possibly a remnant protoplanet prevented from forming into anything bigger by gravitational disturbances from Xerceo."

Example

More examples

"Tyrix, one of the largest objects in Thal's asteroid belt, is a metallic asteroid with an iron-nickel core under a rocky olivine mantle. It is possibly a remnant protoplanet prevented from forming into anything bigger by gravitational disturbances from Xerceo."

Etymology

From proto- + planet.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.