Oxford English Dictionary

An authoritative dictionary that provides the definition and pronunciation of words from the English language. Subscribers can access the online dictionary and make use of worksheets and quizzes. The Word of the Day feature can help you expand your knowledge of the English language.

http://www.oed.com/

MacMillan Dictionaries

A reference website by the MacMillan company. Provides information on the company's products including a line of different dictionaries, both in print and electronic form. The site also has glossaries and a word of the week function to help you improve your vocabulary.

http://www.macmillandictionaries.com

NetDictionary.com

An online reference website that covers a wide variety of terms relating to the Internet. If you have ever wondered what terms like “newbie” mean, then this site will be of interest to you. The dictionary is available in either HTML or Java.

http://www.netdictionary.com/

Merriam-Webster Online

A dictionary and a reference site. You can find definitions of words and medical terms, as well as a Spanish-English dictionary. The site provides a ‘Word of the Day’ function to help you learn more vocabulary. The site also has word games to provide amusement.

http://www.m-w.com/

Wordsmith.org

A website dedicated to the magic of the words. The site's main feature is a “Word of the Day” feature, accessible by email subscription, and which helps to expand your vocabulary. The Worldlovers' Library Project gives copies of "Another Word a Day" for free to libraries and schools around the world.

http://www.wordsmith.org

The Phrase Finder

This website on English words and phrases provides definitions and origins on more than 1,200 English sayings, phrases and idioms. The site also has a phrase thesaurus, a useful tool for professional writers. You can make use of the "a phrase a week" function to learn new phrases.

http://www.phrases.org.uk/

Cambridge Dictionaries Online

A reference service provided by Cambridge University Press. The five dictionaries available here focus on those learning English or wishing to translate it into Spanish and French. There is also a reference service on American English.

http://dictionary.cambridge.org/

TechDictionary.com

An online dictionary where you can look up thousands of technology terms. If you don't quite know how to describe something, you can also enter a key word. The dictionary covers Internet, HTML, telecommunications, computing acronyms and other subjects.

http://www.techdictionary.com/

Word Central

A student dictionary created by Merriam-Webster's to help you improve your vocabulary. The site provides a daily buzzword and games to make learning words more interesting. You can also develop your own words and share them through the site’s "Build Your Own Dictionary" feature.

http://www.wordcentral.com/

Word Origins

Dedicated to the art of etymology, studying the origins of words. The site has reviews of word origin books and other resources that will be of interest to those who want to research word origin in depth. The blog format of the website also makes it easy to learn about word history.

http://www.wordorigins.org/

Investor Words

A specialized dictionary website that provides definitions of financial terms. You can find definitions of terms such as cost of capital, market capitalization, interest rate, compound interest and more. Investor Words has more than 6,000 definitions to help you understand finance better.

http://www.investorwords.com/

Merriam Webster

Merriam Webster is a reference website. You can use the site's dictionary, thesaurus and other tools to improve your fluency with English. The site also provides access to the Encyclopedia Britannica, one of the world's most reliable reference sources.

http://www.m-w.com

RhymeZone.com

RhymeZone is a rhyming dictionary and thesaurus that helps you find all kinds of information on rhymes. You can search for rhymes and other sayings through the site's search function. If you want to share your opinion, you can do so through the site's forum.

http://www.rhymezone.com/

The Free Dictionary

Look up words, acronyms, idioms as well as legal, medical and financial terms. The "Word of the Day" feature helps improve your vocabulary. The site's appearance can be customized to suit your needs.

http://www.thefreedictionary.com/

The Word Detective

The online edition of a humorous newspaper column about words and language, written by Evan Morris. You can read the latest issue of The Word Detective and access a large archive of earlier columns. You can also join the notification list so that you can be informed of new columns whenever they are added to the site.

http://www.word-detective.com/

Word Spy

Word Spy is an online dictionary of new terms and phrases that are daily occurring in the media. The site's archive is easily searched by keyword or subject. You can also find a number of word-related quotations here from authors such as Douglas Adams and Margaret Atwood.

http://www.wordspy.com

Word Wizard

A website for lovers of the English language. You can look up the origin of an English word and get a variety of tips on how to write better English. If you join the site, you can submit your own questions on English usage. The site also has a daily historical diary entry.

http://www.wordwizard.com/

MedTerms

A medical dictionary that defines a variety of medical terms. The site helps people understand the special terminology used by physicians and medical researchers, and can be searched by word or browsed. You can also access the site's “Word of the Day” feature by RSS feed.

http://www.medterms.com/