plutino
Any planetoid in the Kuiper belt whose orbit, like that of Pluto, has a resonance of 3:2 with that of Neptune.
We present a study of the dynamical evolution of plutinos recently escaped from the resonance through numerical simulations. It was shown in previous works the existence of weakly chaotic orbits in the plutino population that diffuse very slowly finally diving into a strong chaotic region.
Where it comes from
From Plut(o) + -ino (“diminutive suffix”), meaning "little Pluto" (compare neutrino); coined by David C. Jewitt, et al.
Adapted from the Wiktionary entry plutino (CC BY-SA 4.0).