-gməs noun
( -es )
Etymology: New Latin, from Greek nystagmos drowsiness; akin to Greek nystazein to doze, sleep, Lithuanian snusti to doze off and perhaps to Greek nythos dark — more at nuance
: a rapid involuntary oscillation of the eyeballs occurring normally with dizziness during and after bodily rotation or abnormally after injuries (as to the cerebellum or the vestibule of the ear)