Parkinson's vs Parkinson's disease

Parkinson's and Parkinson's disease both are nouns.

Word	Noun	Adjective	Verb	Adverb
Parkinson's	Yes	No	No	No
Parkinson's disease	Yes	No	No	No

As nouns, Parkinson's and Parkinson's disease are synonyms defined as:

Parkinson's and Parkinson's disease: a degenerative disorder of the central nervous system characterized by tremor and impaired muscular coordination

Other synonyms of Parkinson's include paralysis agitans, Parkinson's syndrome, Parkinsonism, shaking palsy.

Parkinson's (noun)	Parkinson's disease (noun)
a degenerative disorder of the central nervous system characterized by tremor and impaired muscular coordination	a degenerative disorder of the central nervous system characterized by tremor and impaired muscular coordination