1877, from French maladie de Parkinson (1876), named for English physician James Parkinson (1755-1824), who described it (1817) under the names shaking palsy and paralysis agitans.[Parkinson's disease etymology, Parkinson's disease origin, 英语词源]
1955 (in the "Economist" of Nov. 19), named for its deviser, British historian and journalist Cyril Northcote Parkinson (1909-1993): "work expands to fill the time available for its completion."