Parkinson's disease

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A progressive nervous disease occurring most often after the age of 50, associated with the destruction of brain cells that produce dopamine and characterized by muscular tremor, slowing of movement, partial facial paralysis, peculiarity of gait and posture, and weakness. Also called paralysis agitans, shaking palsy.

Century Dictionary and Cyclopedia

1. n. A form of paralysis, paralysis agitans (which see, under paralysis), described by Parkinson in 1817.

Wiktionary

1. n. neurology, pathology A chronic neurological disorder resulting in lack of control over movement; poor balance and coordination; and similar symptoms.

WordNet 3.0

1. n. a degenerative disorder of the central nervous system characterized by tremor and impaired muscular coordination