Wordo is described as 'co is the clean and social dictionary, loved by word-geeks, Wiktionary enthousiasts and students' and is a Dictionary in the Education & Reference category. There are more than 10 alternatives to Wordo, not only websites but also apps for a variety of platforms, including iPhone, Android, iPad and Chrome OS. Most alternatives are Dictionaries and Translator Apps. The best alternative is Wiktionary, which is both free and Open Source. Other great sites and apps similar to Wordo are WordReference (Freemium), Merriam-Webster (Free), Dictionary.com (Free) and Google Dictionary (Free).
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.
Online Dictionary - Multiple dictionaries including: English dictionary, medical dictionary, legal dictionary, financial dictionary, computer dictionary, thesaurus, dictionary of acronyms and abbreviations, dictionary of idioms, thesaurus, Columbia encyclopedia, Wikipedia...
Lion allows you to send a query to the German-English, -French, -Spanish and -Italian LEO dictionaries (Chinese is currently not supported) with a click of your mouse from almost all MS Windows applications.