Dictionaries (Online)--English and Multilingual 
Encyclopedias, Thesauri, Translations

Free Dictionary Apps for English Language Learners

Dictionaries

***Cambridge Academic Content Dictionary <http://dictionary.cambridge.org/dictionary/american-english/> -- key academic terms as well as a broad range of everyday meanings, best for intermediate and upper-intermediate students; includes phrasal verbs, sound, example sentences

***Longman Dictionary of Contemporary English Online (LDOCE) <http://www.ldoceonline.com/> -- IPA in British and American English, countable/non-countable, levels of formality and politeness;  idiomatic expressions--some with pronunciation (British English and American English, depending on usage), sample sentences with pronunciation, sentence usage notes (e.g. determine how/whether/what, etc.)

***Vocabulary <http://www.vocabulary.com/dictionary/> -- includes sound for pronunciation (American English); just start typing a word and the dictionary will display the most likely results, including related words (word families); word families are shown with links to definitions; usage examples show the word in several different genres; narrative definitions (easy to understand)

***Merriam-Webster's Learner's Dictionary <http://www.learnersdictionary.com/> -- includes sound for pronunciation and phrasal verbs (v + prep); American English Dictionary for ESL, EFL, and TOEFL® students; a super tool: Create your own online vocabulary flashcards with My Learner's Dictionary (must get a free account to log in); other great tools: 3,000 Words—you need to know! Perfect Pronunciation Exercises, subscription to Learner's Word of the Day

***TheFreeDictionary.com <http://www.thefreedictionary.com> -- includes includes sound for pronunciation, related word forms and phrasal verbs (v + prep); see links to Dictionary / Thesaurus, Idioms Medical Dictionary, Legal Dictionary, Financial Dictionary, Acronyms, Encyclopedia.

Answers.com <http://www.answers.com/> -- includes sound for pronunciation (note the WordTutor, which gives the pronunciation in slowed-down speech along with definitions and example sentences using the word); inflected word forms and related word forms (adj, n, v), synonyms, antonyms, etymology (origin) of words, some encyclopedia entries, translations for the word into different languages (user can set preferred language/s), and a ready-made citation for MLA, APA, or Chicago Style Manual.

***NetDictionary <http://www.edict.com.hk/lexiconindex/> -- dictionary gives synonyms and related word forms for words; shows collocations for words and strings of words (e.g. phrasal verbs) and has links to text-to-speech audio files for entries

Merriam-Webster's Dictionary <http://www.merriam-webster.com/> -- for native speakers, inflected word forms and related word forms (adj, n, v), as well as the date of first occurrence! A basic, but complete online English dictionary and thesaurus; includes Word of the Day, Word for the Wise, Word Game of the Day, Words from the Lighter Side.

OneLook <http://www.onelook.com/> -- gives quick definitions but also looks up a word in many different dictionary sites and allows you to choose which one to visit; includes links to special dictionaries--General, Art, Business, Computing, Medicine, Miscellaneous, Religion, Science, Slang, Sports, Tech, Phrases; links to many dictionaries for translation.

bab.la Dictionary <http://en.bab.la/dictionary/> -- dictionary for English to 25 other languages; also includes appropriate Phrases in different registers (academic, business, application, personal, travel, immigration) and Conjugations for several languages.

***yourDictionary.com <http://www.yourdictionary.com/> -- a web of dictionaries, online grammars of many languages, and linguistic fun (historical linguistics, phonology, morphology, semantics, psycholinguistics): includes Multiple Dictionary Search Engines, Thesauri & Other Vocabulary Aids (acronyms, abbreviations, synonyms, homonyms, anagrams), Phrase Dictionaries, Quotations, Quotes of the Day/Week & Quote Searches, Lexicography & Lexical Databases/Corpora), Pronunciation & Rhyming Dictionaries, Etymological Dictionaries, Multilanguage Dictionaries (for 171 languages, including Japanese, Thai, Korean, African languages, all European languages), Specialized English Dictionaries (for 66 subject areas), Translations for all European languages, international Dictionary Indices, Language Identifiers and Guessers

***LookWAYup <http://lookwayup.com/free/> -- instantly look up a word by having the dictionary on your toolbar!  It is a browser add-on that combines dictionary, thesaurus, translation, and advanced search tool; full version with translation en français; auf Deutsch; en español; in Nederlands; em português.

***VoyCabulary <(http://www.voycabulary.com/> -- a glossing tool; VoyCabulary^(tm) makes the words on any webpage into links so you can look them up with just a click!  It links every word to a dictionary (e.g. Merriam Webster with sound, acronym/computer/medical/law dictionary) or thesaurus; Spanish.Voycabulary.com; Science.Voycabulary.com; English.Voycabulary.com

POPjisyo.com <www.popjisyo.com> -- POPjisyo is a web based pop-up dictionary for Japanese, Chinese, Korean and other languages.
Read foreign language web sites with pop-up hints by moving the mouse over words you want to lookup! (link contributed by Stephanie Reynolds, CALL Online class, summer 2008)

***Infoplease <http://www.infoplease.com/>-- a dictionary and encyclopedia; includes Almanacs; Atlas; Dictionary; Encyclopedia; > 30,000 biographies; This Day in History; Today's Birthdays; Today's News; Facts Behind the News; What Does It Mean?; Crossword, Timeline: Asian-American History, Year-by-Year Chronology--1900–2002;

The American Heritage^® Dictionary of the English Language <http://www.bartleby.com/61/> -- Over 90,000 entries feature 10,000 new words and senses, 70,000 audio word pronunciations, 900 full-page color illustrations, language notes and word-root appendixes.

Newbury House Online Dictionary <http://nhd.heinle.com/> -- 40,000 entries, so-so; includes Cultural Note of the Day

Alpha Dictionary <http://www.alphadictionary.com/index.shtml> -- includes "Today's Good Word" (expressions) with pronunciation, Fun and Games, links to other language dictionaries and grammars, discussion list of words and language (link contributed by Beth Ann Cope)

Middle English Dictionary <http://www.hti.umich.edu/dict/med/> -- "Its projected 15,000 odd pages offer a comprehensive analysis of lexicon and usage for the period 1100-1500."

OneLook Dictionaries <http://www.onelook.com> -- A search engine designed to search various online dictionaries.

The Online Slang Dictionary <http://www.ocf.berkeley.edu/~wrader/slang/> -- Walter Rader's collection of English slang

Synonym Dictionary <http://vancouver-webpages.com/synonyms.html>

The Devil's Dictionary <http://www.alcyone.com/max/lit/devils/> -- By Ambrose Bierce

Singlish Dictionary <http://www.sol.com.sg/virtual/singlish.html> -- English as spoken in Singapore

Yahoo Reference - Dictionaries <http://www.yahoo.com/Reference/Dictionaries/> -- Shortcut to Yahoo's collection of online dictionaries

The Electronic Literature Directory <http://directory.eliterature.org>

Webopedia <http://www.webopedia.com/> -- The only online dictionary and search engine you need for computer and Internet technology.

Dictionaries of Business Terms

BusinessDictionary.com <http://www.businessdictionary.com/> -- 20,000 terms and phrases from business

Interactive Terminology for Europe <http://iate.europa.eu/iatediff/SearchByQueryLoad.do?method=load> -- 24 source & target languages and 21 domains/areas, including politics, international relations, European communities, law, economics, trade, finance, social questions, education and communications, science, business and competition, employment and working conditions, transport, environment, agriculture/forestry/fisheries, agrifoodstuffs, production/technology/research, energy, industry, geography, international organizations (site contributed by Eleni Makri, CALL Online summer 2008)

Picture Dictionaries

eflnet Picture Vocabulary <https://eflnet.com/vocab/picturevocab.php> -- topics from A to Z; words with images; exercises (drag and drop, multiple choice, matching), games, puzzles to practice

Internet Picture Dictionary <http://www.pdictionary.com/> for English, French, German, Italian, Spanish; search by letter or category; links include Flashcards, Fill-in-the-blanks, Word Scramble, Stinky Spelling, Straight Recall; Other pdictionaries...

EnchantedLearning <http://www.enchantedlearning.com/Home.html> -- K-12 focus; pictures on many topics, with lots of activities, quizzes, worksheets, added daily!

Encyclopedias

Encyclopedia Britannica <http://britannica.com/> -- on-line access to the contents of the encyclopedia's massive database of information; citations provided in MLA and APA style

Wikipedia <http://www.wikipedia.com) -- online encyclopedia in a Wiki (collaborative space); good for terms in technology; not for academic use/citations but sometimes has good references

Encyclopedia.com <http://www.encyclopedia.com/> -- citations in MLA and APA style provided

Columbia Encyclopedia <http://www.bartleby.com/65/> -- a literary encyclopedia
Quotations <http://www.bartleby.com/quotations/> -- an encyclopedia of quotations

Infoplease <http://www.infoplease.com/>-- a dictionary and encyclopedia; includes Almanacs; Atlas; Dictionary; Encyclopedia; > 30,000 biographies; This Day in History; Today's Birthdays; Today's News; Facts Behind the News; What Does It Mean?; Crossword, Timeline: Asian-American History, Year-by-Year Chronology--1900–2002;

Answers.com - Encyclopedia <http://www.answers.com/library/Encyclopedia> -- General reference, with places, events, historical facts, people and terms, listed alphabetically and by category

Webopedia <http://www.webopedia.com/> -- The only online dictionary and search engine you need for computer and Internet technology.

Thesauri

***Power Thesaurus <https://www.powerthesaurus.org> -- includes pronunciation, synonyms and antonyms with parts of speech, definitions, and examples; shows recently searched words

***Cambridge Academic Content Dictionary <http://dictionary.cambridge.org/dictionary/american-english/> -- includes a thesaurus for topics in Business, Finance, Clothes, Education, Light and colour, Personal care

The Free Thesaurus <http://www.freethesaurus.com/> -- comprehensive online thesaurus of synonyms, antonyms, and related words; contains more than 145,800 unique entries; can be filtered by part of speech

Roget's Thesaurus <http://humanities.uchicago.edu/forms_unrest/ROGET.html>
Roget's II: The New Thesaurus <http://www.bartleby.com/62/> -- 3rd ed., searchable database of 35,000 synonyms and more than 250,000 cross-references

Merriam-Webster OnLine Dictionary <http://www.m-w.com/dictionary.htm> -- from Merriam-Webster, includes etymology and a built-in-thesaurus.

Dictionary.com  <http://thesaurus.reference.com/> 

Synonym Dictionary <http://vancouver-webpages.com/synonyms.html>

Lexical FreeNet-Connected Thesaurus <http://www.lexfn.com/> -- finds related words, concepts, famous names

Visual Thesaurus <http://thesaurus.plumbdesign.com/index.jsp> -- An experiment in language and interface, Plumb Design's Visual Thesaurus is both an artistic exploration and a tool to explore, study, and analyze the structure of language. By displaying the interrelationships between words and meanings as spatial maps, the Visual Thesaurus translates language into a visible architecture.

Translations

Google Translate <https://translate.google.com/> -- translate from many languages

Lingro <http://lingro.com/> -- a multi-language glossing tool; enter a Web page and click words to get glosses in other languages.

Babylon <http://www.babylon.com/define/22/Business-Dictionary.html> -- free Business Terms Lookup that comprises more than 10 dictionaries, among others, such well known titles as Campbell R. Harvey's Hypertextual Finance Glossary, MONASH Marketing Dictionary, and the European Central Bank Glossary. Provided by Babylon Online Dictionaries.

Babylon <http://www.babylon.com/define/136/Wirtschaft-Lexikon.html> -- free German-English business/trade/accounting dictionaries and glossaries

NiceTranslator <www.Nicetranslator.com> --  Downloadsquad.com wrote: "Nice Translator is powered by Google Translate, so you get the same results from Google. But the interface is incredibly easy to use. Just select the languages you want to translate text into and start typing. Nice Translator will convert your words as soon as you type them." 

Blueseal Dictionary <http://dict.blueseal.eu> -- for translations from English to German, Spanish, and French, and vice versa

Dict.cc <http://www.dict.cc/> -- translations from English to German

LEO <http://dict.leo.org/> -- translations to German from French, Spanish, Italian, Chinese, Russian, Portuguese, Polish

Free Translations <http://www.freetranslation.com>

Dictionary.com <http://dictionary.reference.com/translate/text.html>

OneLook <http://www.onelook.com/> -- links to many dictionaries for translation

travLang's Word of the Day <http://travlang.com/wordofday/> -- subscription for Word of the Day, including pronunciation, in many languages