Parkinson's syndrome vs Parkinson's disease

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

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

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

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

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

Parkinson's syndrome (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