Chosen as "Best Dictionary App" by the book "Best Android Apps: The Guide for Discriminating Downloaders", O'Reilly Media.

Free Dictionary is an English Dictionary that gives you English definitions, synonyms, pronunciation and spelling.
- Auto-suggestion
- Offline Database query when there is no network
- Wikipedia Integration
- Play quiz game
- Searched word on Google Images
- Search history

Kudos Wiktionary Word of the day APP and WIDGET.

Learn a new word everday by either launching the app or including a widget on your home screen (To add a widget after installing the app tap on an empty part of your background and select 'widgets' then 'Wiktionary')
Tapping the widget will give a full explanation of the word.

Dictionary data taken from wiktionary.com
Parts of the source are taken from or modified versions of that found on the Android Developer Blog.

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 encyclopedia, Hutchinson encyclopedia, examples from classic literature, pronunciations, word browser, glossary. Free access.

Application unofficial The Free Dictionary, thefreedictionary.

DictionaryForMIDs is a multi-purpose, offline dictionary application. Many dictionaries are available for automatic (may take a while) or manual installation, you can even create your own dictionary using tools from the website.