planetoid

noun

Etymology: Etymology tree English planet Ancient Greek -ο- (-o-)der. Latin -o- Proto-Indo-European *weyd- Proto-Indo-European *-os Proto-Indo-European *wéydos Proto-Hellenic *wéidos Ancient Greek εἶδος (eîdos) Proto-Indo-European *-os Proto-Indo-European *-ēs Ancient Greek -ης (-ēs) Ancient Greek -ειδής (-eidḗs) Latin -oīdēslbor. English -oid English planetoid From planet + -oid.

1. An asteroid of any size

   “The group of small bodies that circle round the Sun, outside the orbit of Mars, are known under the designation of the planetoids.”

   “Numbering of the Planetoids or Asteroidal Planets.—In numbering the planetoids a difficulty has arisen [...]”

2. An asteroid-like body in an orbit beyond the asteroid belt, such as a centaur or Kuiper belt object
3. A larger, planetary, body in orbit around the Sun, such as Vesta or (candidate) dwarf planets such Eris or Sedna

   “After discovering "planetoids", bodies orbiting the Sun, even larger than Pluto's moon Charon ... the question of how Sedna and other planetoids came to be.”

   “Eris [...] was the upstart planetoid that knocked Pluto off the planetary lists”

4. Any planetary body, including classical planets and moons: a planetary-mass object

   “Plate tectonics is a style of convection for an active planetoid where lid fragment (plate) motions reflect sinking of dense lithosphere in subduction zones […] In 2015 humanity completed a 50+ year effort to survey the 30 largest planets, asteroids, satellites, and inner Kuiper Belt objects, which we informally call “planetoids”.”

5. A dwarf planet

   “We prefer the word "planetoid" as a new word to describe round objects orbiting the sun.”

   “A dwarf planet or a planetoid is a celestial body that [...]”