Deutsches Wörterbuch von Jacob und Wilhelm Grimm im Internet

Generally considered the most extensive dictionary of the German language. Started by the brothers Jacob and Wilhelm Grimm in 1838, the dictionary took well over 100 years to be completed in 1961 with its 32nd volume and revisions for an updated edition are currently under way in Berlin and Göttingen. The Grimm dictionary illustrates the history of the German language since 1450 with over 331,000 entries and citations from approximately 4,000 sources.