Search Result for "essential tremor":
Wordnet 3.0

NOUN (1)

1. tremor of unknown cause (usually of the hands and head) that develops in older people; often mistaken for Parkinsonism but is not life-threatening and can usually be kept under control; 



WordNet (r) 3.0 (2006):

essential tremor
    n 1: tremor of unknown cause (usually of the hands and head)
         that develops in older people; often mistaken for
         Parkinsonism but is not life-threatening and can usually be
         kept under control