Acronym and Abbreviation Dictionary
Dictionary of acronyms and abbreviations.
http://www.ucc.ie/info/net/acronyms/index.html

Cambridge International Dictionaries online
Use this free online resource from Cambridge University Press and search for words, phrases and idioms.
http://dictionary.cambridge.org/

Dictionary of Mountain Bike Slang
Compiled by Jim Frost.
http://world.std.com/~jimf/biking/slang.html

Dictionary of Occupational Titles
A listing of thousands of job titles.
http://www.wave.net/upg/immigration/dot_index.html

List of Dictionaries
One of the best collections of links to dictionaries from all over the world.
http://math-www.uni-paderborn.de/HTML/Dictionaries.html

Macmillan Dictionary
The resource site for the Macmillan English Dictionary offering articles, e-lessons, the MED Magazine and resources.
http://www.macmillandictionary.com

Medspeak: The Dictionary of ER
Lots of medical terms from the popular American television program, ER.
http://www.geocities.com/TelevisionCity/5196/index.html

Merriam-Webster Online Dictionary
From Merriam-Webster, searches include pronunciation, etymology, and a built-in thesaurus. Probably the very best English dictionary on the Web. Highly recommended!
http://www.merriam-webster.com/

Multiculturalpedia
Dictionary of multicultural daily customs/culture. Dedicated in enhancing awareness towards cultural diversity and fulfilling human desire for mutual understanding.
http://www.netlaputa.ne.jp/~tokyo3/e/

New Zealand English to U.S. English Dictionary
A good place to brush up on your Kiwi English.
http://nz.com/NZ/Culture/NZDic.html

Newlingo Internet Language Dictionary
A comprehensive listing of new vocabulary from the World Wide Web.
http://www.netlingo.com/

OneLook Dictionaries
805,535 words indexed from 186 dictionaries. Wow!
http://www.onelook.com/

Roget's Thesaurus
Online version of this timeless classic.
http://humanities.uchicago.edu/forms_unrest/ROGET.html

Schackne Online-Reference
Comprehensive Dictionary Category
http://www.schackne.com/Reference.htm

Synonym Dictionary
This cool page generates copyright-free lists of English synonyms.
http://vancouver-webpages.com/synonyms.html

Transgem
Technical online dictionary of expressions: German-English and English-German
http://www.transgem.de/

WordNet 1.5 Vocabulary Helper
Fast and easy to use, this online dictionary is on par with WWWebster.
http://www.notredame.ac.jp/cgi-bin/wn