It is easy to understand what a sednoid is. A sednoid is a trans-Neptunian object.
Its perihelion exceeds 50 AU from the Sun, that is, farther than Neptune.
These objects form a lot of sub-objects (they are divided into many pieces).
The sednoid is "an object of Oort's cloud."
This explanation started with Chadwick A. Trujillo and Scott S. Sheppard, who began studying these objects in 2012.
They called the 2012 Transneptunian VP a new discovery.
Only since 2013 is the term Sednoid used, taken from the trans-Neptunian object, called Sedna.