Not only is that icy world at the fringe of the solar system no longer a planet, but, as LiveScience reports, it’s no longer even a dwarf planet. It’s something else altogether – a “plutoid”:
Here’s the official new definition:
“Plutoids are celestial bodies in orbit around the sun at a distance greater than that of Neptune that have sufficient mass for their self-gravity to overcome rigid body forces so that they assume a hydrostatic equilibrium (near-spherical) shape, and that have not cleared the neighborhood around their orbit.”
In short: small round things beyond Neptune that orbit the sun and have lots of rocky neighbors.
The two known and named plutoids are Pluto and Eris, the IAU stated. The organization expects more plutoids will be found.
Yes, it’s unfortunate terminology.