Duden German Dictionaries is described as 'Seven Duden German dictionaries with audio pronunciations recorded by native speakers' and is an app in the Education & Reference category. There are three alternatives to Duden German Dictionaries for Android, Chrome OS, Google Chrome, Mac and Online / Web-based. The best alternative is Wiktionary, which is both free and Open Source. Other great apps like Duden German Dictionaries are Google Dictionary (Free) and Apple Dictionary (Free Personal).
Google's dictionary extension on Google Chrome. With it, you can double-click any word to view its definition in a small pop-up bubble, or search the complete definition of any word or phrase using the address bar dictionary.