The story
From Plut(o) + -ino (“diminutive suffix”), meaning "little Pluto" (compare neutrino); coined by David C. Jewitt, et al.
Etymology from Wiktionary, CC BY-SA 4.0.
plutino
Today it means: Any planetoid in the Kuiper belt whose orbit, like that of Pluto, has a resonance of 3:2 with that of Neptune. Full definition →