As you read through various definitions for dictionary most of the definitions include the word book as part of the definition. Yet, there is not question that online dictionaries abound. My preferred definition of dictionary as it relates to this post is…”a book [resource] giving information on particular subjects or on a particular class of words, names, or facts, usually arranged alphabetically: a biographical dictionary; a dictionary of mathematics.” In not particular order (though I will admit the first three are my personal favorites), I have listed several online dictionaries below:

1. Dictionary.com – In addition to looking up a definitions this site include a myriad of additional accessories/functions:
   • Word of the Day
   • Spanish Word of the Day
   • Dictionary.Com Word Explorer Podcast link
   • Word games
   • Crossword solver tool
   • Daily crossword
   • Full-text translator
   • Multilingual dictionary (translator)
   • Special link options that can be included on a web or blog
   • more…
2. Visuwords Online Graphical Dictionary – this fascinating interface produces diagrams that include meanings and word associations with other words and concepts. It’s a thesaurus, as well as a dictionary.
3. Merriam Webster Dictionary and Thesaurus – enter a word or phrase to view the definition and hear the word pronounced. The site also includes the following:
   • Word of the Day
   • Excellent Interactive Word Games (sadly, they are no commercial free, but hey they are free…)
   • Spelling Bee Information
   • Special Features for Kids: Word Central and Spell It!
   • Medical Dictionary
   • Spanish/English Dictionary
   • Visual Dictionary – an interactive dictionary that includes an image with the word and its definition, the Visual Dictionary Online is an all-in-one reference. “Search the themes to quickly locate words, or find the meaning of a word by viewing the image it represents.” Don’t miss the games and tools sections of this site. You can use the tools to legally “nab” some great images for curricular purposes.
4. Free Dictionary.com – “The world’s most comprehensive dictionary: English, Spanish, German, French, Italian, Chinese, Portuguese, Dutch, Norwegian, Greek, Russian, Medical, Legal, and Financial Dictionaries, Thesaurus, Acronyms and Abbreviations, Idioms, Encyclopedia, a Literature Reference Library, and a Search Engine all in one!”
5. Leximo – “Leximo is a ‘Social Dictionary’ that invites users to submit words in every spoken language of the world. Since each word can be submitted by multiple users, definitions can vary widely in quality and thus other users can rank these definitions, so that the most popular definitions appear first.”
6. Urban Dictionary – you may want to block this one in your schools, as it is a social slang dictionary that gives users a venue to write their own definitions. The dictionary is an interesting read and may help you decipher what your students are referring to when they sling around their slang.
7. One Look – this is a marvelous little dictionary that has indexed 13,587,880 words from 1024 dictionaries. It includes wildcard search capability and an impressive reverse dictionary option.
8. Your Dictionary – “a free online dictionary and much more. The free dictionary search gives you definitions, thesaurus entries, spelling, pronunciation, and etymology results for your word. Alternatively, you can browse the English dictionary alphabetically or by related terms to find meanings and synonyms. In addition, Your Dictionary provides resources to help you find the best dictionary and translation sites for French, Spanish, Italian, German and hundreds of other languages…Your Dictionary can help you find the best customized resources including a pharmaceutical and medical dictionary list, computer and science glossaries and a wide collection of industry specific terms. These extensive references are useful for students trying to further their education and learn the vocabulary of a field of study as well as for seasoned professionals.” And…it also has some great interactive word games!
9. Alpha Dictionary.com – search 1065 online English dictionaries at once! Explore the site for some clever word lists, games, specialty glossaries and more…don’t be led astray by the numerous advertisement links…the only down side to the site (in my humble opinion).
10. Cambridge Dictionaries Online – a very simple input form that allows you to look for words/phrases using a number of different dictionaries (I liked the idiom dictionary)
11. definr – it’s not fancy, but it’s fast!
12. Enchanted Learning Little Explorers Picture Dictionary
13. Webster’s Online Dictionary – includes word of the day, hour, minute in addition to definitions, quotes, and more
14. Rhymezone – Type in a word to find its rhymes, synonyms, definitions, and more:
15. A Math’s Dictionary for Kids – search math terms
16. Dictionary Law.com – search legal terms
17. A Dictionary of Philosophical Terms and Names
18. Wordsmyth – “the premier educational dictionary/thesaurus” Choose between a beginner, children, and advance dictionary as you look for words. The site is in the midst of a re-design project that includes some new features. Check out the matching quiz builder function, reverse search, anagram solver, fill-in maker, and more.
19. Yahoo Kids.com – “an alphabetical list of words that tells you what each word means, how to say the word, and where the word comes from.”
20. The Internet Picture Dictionary – great for ESL and younger students. Simply browse by letter, word, or category. The site includes some simple activities like flashcards, word scrambles, and more.
21. Mondofacto – “he mondofacto dictionary is a dictionary of terms relating to biochemistry, cell biology, chemistry, medicine, plant biology, technology and zoology – in fact anything to do with science and medicine. It includes acronyms, conventions, eponyms, and history.”
22. Epicurious Food Dictionary – “more than 4,000 food terms and you’ll never have to eat your words.”
23. Kid-Friendly Medical Dictionary – a small, but comprehensive list of medical terms you can share and use with your students and children.
24. LingoZ – an online community dedicated to the building of the world’s largest dictionary. Registered users are allowed to add new terms, definitions and translations, glossaries, comment, rate and to collaborate with others on any content item. LingoZ is a service by Babylon, the world’s leading provider of translation software.
25. Answers.com – an answer engine, with quick accurate dictionary, thesaurus, encyclopedia, bios, tech terms, news, sports, weather, and much more.

And here is a little bonus site…

Save the Words – a fun, engaging site where you (and your students) can adopt and save a word that is not used frequently. As students click on the words they will be able to view a definition of the word and can see how the word is used in a sentence.