'Nystagmus' definitions:

Definition of 'nystagmus'

From: WordNet
noun
Involuntary movements of the eyeballs; its presence or absence is used to diagnose a variety of neurological and visual disorders

Definition of 'Nystagmus'

From: GCIDE
  • Nystagmus \Nys*tag"mus\, n. [NL., fr. Gr. ? drowsiness, fr. ? to nod in sleep, to slumber.] (Med.) A rapid involuntary oscillation of the eyeballs. [1913 Webster]