Dictionaries & Thesauri

How do you spell onomatopeoia? What are twelve different ways to say "ugly"? Aren't dictionaries and thesauri fun?

Cambridge Dictionaries Online	Includes four dictionaries: learner's, American English, idioms and phrasal verbs.
Dictionary.com/ Thesaurus.com	Free online English dictionary, thesaurus and reference guide, crossword puzzles and other word games, online translator and Word of the Day.
Foreignword.com	Includes links to hundreds of online multilingual and monolingual dictionaries, including ones that will translate entire blocks of text from one language to another.
Merriam-Webster's Collegiate Dictionary	This classic, comprehensive dictionary is easy to search and features a link to the Collegiate Thesaurus for quick synonyms.
One Look	Searches in over 600 on-line dictionaries. Includes options for other languages as well as English.
Your Dictionary.com	In additon to an English-language dictionary and thesaurus, this site contains 240 foreign language dictionaries as well as rhyming, speciality, and pronouncing dictionaries.