9 letters · 15 points in Scrabble
noun involuntary movements of the eyeballs; its presence or absence is used to diagnose a variety of neurological and visual disorders
originFirst attested in 1798. From New Latin nystagmus, from Ancient Greek νυσταγμός (nustagmós, “nodding, drowsiness”), from νυστάζω (nustázō, “nod, be sleepy”).
Etymology from Wiktionary, CC BY-SA 3.0