Merriam-Webster Dictionary  - official site for the reference publisher. Includes online versions of the collegiate dictionary and thesaurus.

OneLook Dictionaries  - search for multiple definitions of a word from a variety of online dictionaries.

allwords.com - English dictionary with multi-lingual search capability. Includes crossword solver features.

American Heritage Dictionary of the English Language, Fourth Edition - features over 90,000 entries, most with audio word pronunciations.

AskOxford.com   - contains a dictionary and thesaurus, as well as quotations, word of the day, games, and lexicography.

Cambridge International Dictionaries - search separate dictionaries of English, phrasal verbs, or idioms.

Century Dictionary Online - American dictionary with fulltext search page images representing the definitions, atlas, and cyclopedia from the original text.

CoolDictionary.Com: Audible Webster Dictionary - features audio clips of words and quotes.

DICT Development Group  - simultaneously search several dictionaries for word definitions including Websters, Jargon File, and other databases.

Dictionary of American Regional English - specializes in regional words and phrases.

Dictionary.com - features a variety of tools including thesauri, translator, and writing resources.

Encarta World English Dictionary - features audio clips of words pronounced.

FreeDictionary.org - simultaneously and efficiently searches several dictionaries for word definitions.

Google Glossary - find definitions, phrases, and acronyms.

HyperDictionary - displays definitions with each individual word in the definition hyperlinked to its definition.

Hypertext Webster Gateway - offers point-and-click interface for accessing various dictionary services on the Internet.

iTools Language Tools - features dictionary, thesaurus, and translation tools.

LookWAYup - dictionary and search tool embedded into the web page.

VoyCabulary - makes the words on any webpage into links so you can look them up in a dictionary or other reference site, by simply clicking on the words.

WebRef.org - providing glossaries of terms related to various scientific disciplines, aesthetic arts, and biographical information.

Word Assault - searches various dictionaries for multiple words at a time.

WordNet - online dictionary that finds words that mean the same, are more general, or more specific.

Wordsmyth Educational Dictionary-Thesaurus - American English dictionary with an integrated thesaurus and other lexical resources.

Yahoo! Reference - provides dictionary, encyclopedia, quotation, and world fact resources.

From Language to Language  - multilingual translation dictionary.

Dictionary of English Phonesthemes - phonesthemes, or sound-symbols, play an important role in word-formation and psycholinguistics.

English-Kurdish Dictionary - provides translations of words.

Eurodicautom - European Commission's multilingual term bank, with a focus on technical and specialized terminology.

Internet Picture Dictionary - multilingual picture dictionary with interactive activities for learning English, French, German, Spanish, and Italian.

Mingo Egads - texts, grammar, dictionary, and learning resources for this Iroquoian language.

Terminological Information System (TIS) - online version of the database used by terminologists and translators working in the General Secretariat of the Council of the European Union.

Travlang's Translating Dictionaries - multilingual online dictionaries including German, French, Spanish, English, Dutch, Danish, Afrikaans, Esperanto, Frisian, and more.

Ukrainian Online Dictionaries

WordReference.com - enables website visitors to double-click any English word for a definition or translation.

WordSniffer - multi-lingual dictionary for English, German, French, Spanish, Italian, Japanese, Chinese, and more. Offers definitions, pronunciations, and sample sentences.

Symbols.com  - information on more than 2,500 western signs and ideograms.

American Business Jargon Dictionary - dictionary of American business jargon from above board to zilch, zip, and zombie bonds.

Biographical Dictionary - covers notable men and women who have shaped the world from ancient times to the present day.

Biography Center - multi-lingual biographical directory.

Bushido Online - encyclopedia exploring the history and philosophy of Bushido. Includes its relation to Kung Fu, Karate, and Kobudo.

Dictionary of Mountain Bike Slang - expressions for the trail-savvy.

Dictionary of Occupational Titles (DOT) Index - alphabetical index to the revised fourth edition, 1991.

Dictionary of Phrase and Fable - giving the derivation, source, or origin of common phrases, allusions, and words that have a tale to tell.

DOD Dictionary of Military and Associated Terms

Glossary of Social Science Computer and Social Science Data Terms - includes terms which may be useful in managing data collections and providing basic data services.

Illustrated Dictionary of Jewelry - includes jewel terms, mineralogy, jewelry manufacturers, jewelry styles, gemstone cuts, etc.

Jane's Internet Defence Glossary - thousands of defence related acronyms and abbreviations.

Movie Terminology Glossary - definitions of terms and phrases frequently used in the world of movies, film, acting, and cinemagoing.

Nonverbal Dictionary, The - gestures, signs, and body language cues, from adam's-apple-jump to zygomatic smile.

ODLIS: Online Dictionary of Library and Information Science

Online Film Dictionary - reference for movie terms in foreign languages.

Pimbley's Dictionary of Heraldry

Poker Dictionary - lexicographic exploration of the popular card game.

Poker Glossary - terms and definitions for basic poker play.

Political Dictionary - non-partisan dictionary covering contemporary politics.

Samuel Adams Beer Dictionary - from ale to zymurgy, the science of brewing.

Space & Electronic Warfare Lexicon - collection of technical terms, acronyms, mission areas, taxonomies, and citations relating primarily to Naval electronic warfare and space warfare.

Alternative Dictionaries - collaborative international slang dictionary.

Alternative Dictionaries, The - collaborative Internet project collating slang from languages around the world.

Alternative Turkish Dictionary - express yourself brusquely with the aid of this abbreviated Turkish-English slang dictionary.

American Cultural Knowledge for Confused New Zealanders - includes NZ words and their U.S. "translations".

Australian Slang - learn these words and phrases and you'll feel at home on your first day Down Under.

Boston Slanguage

BuzzWhack - buzzword-compliant dictionary provides definitions for business buzzwords, slang, and jargon.

College Slang Page: Da Bomb - the 411 on the hip talk in the hallowed halls.

Dictionary of American Regional English - specializes in regional words and phrases.

Dictionary of Mountain Bike Slang - expressions for the trail-savvy.

Dictionary of Slang - collection of slang currently used in Britain, including slang links, bibliography, and related articles.

English-to-American Dictionary - ever wondered how to snog? What sort of blokes pull birds? For Americans learning Scottish English.

Gay Slang Dictionary - collection of slang terms used in the gay community. Submit your own.

Jom Ngomong2x - comparisons of Indonesian and Malaysian slang.

Kiwi Words & Phrases - light-hearted look at words and expressions commonly used in New Zealand.

Limerick/Dublin Slang Dictionary. - dictionary of slang words from Limerick and their Dublin equivalent

London Slang - deals with slang usage in and around London.

New Words in English - neologisms and novel uses of words in English. The words give a good picture of the creative aspects of word formation and use in present day English.

New Zealand Expressions - list of expression and words commonly used in New Zealand followed by the U.S. equivalent definition.

Nonsensicon, The - non existent words and their meaning.

Online Dictionary of Playground Slang - indexed dictionary of colloquialisms and slang words (past and present) used throughout the English-speaking world.

Online Dictionary of Street Drug Slang - searchable dictionary with thousands of slang terms.

Online Slang Dictionary

Pseudo Dictionary  - compiling words that people may use all the time that aren't in a normal dictionary. Includes slang, webspeak, and colloquialisms. Submissions welcome.

Rap Dictionary - resource for hip-hop slang.

Scottish Slang Productions - collection of Scottish slang phrases recorded in and around London by true Scots. WAV and Real Audio files available.

Scullerypress - an online slang dictionary from the Inverclyde area.

Seattle Lexicon, A - rundown on some of the peculiarly local lingo.

SlangSite.com - dictionary of slang, webspeak, made up words, and colloquialisms.

Some Irish Slangwords

Surfing for Slang: Recommended Slang Links - links to English and Scandinavian slang-related sites.

Twists, Slugs and Roscoes: A Glossary of Hardboiled Slang - the language spoken by Philip Marlowe, Sam Spade, Mike Hammer. With the help of this glossary, you too can speak it like a native.

Urban Dictionary - define your world and submit words for others to see.

Ye Olde English Sayings - examining the origins of phrases often taken for granted.

FAQ - Naval Terminology, Jargon and Slang - derived from the royal navies of the former British Empire.