Bab.la!

The free Dictionary.com app delivers content from Dictionary.com and Thesaurus.com, including nearly a million words and definitions and 90,000 synonyms and antonyms. No internet required!

Free online dictionary, thesaurus, spanish-english and medical dictionaries, audio pronunciations, Word of the Day, word games, and many more high-quality Merriam-Webster language resources.

Free online dictionary of British English and American English from Oxford. Translate from English to Spanish, French, Italian, and German with bilingual dictionaries. Get writing, spelling and grammar help, and play word games. (US)

Cambridge University Press has been publishing dictionaries for learners of English since 1995. Cambridge Dictionaries Online has been offering these dictionaries completely free of charge since 1999.

Advanced English Dictionary is better than other dictionaries, not just because it contains far more words than a conventional paper dictionary, but because it uses a radically new approach to searching for words. Instead of just listing the words and their definitions, AED shows how every word is linked to another.

The Longman Dictionary of Contemporary English Online is an online version of the CD-ROM of the Longman Dictionary of Contemporary English, Updated Edition.