American Heritage Dictionary. Fourth Edition. Searchable.
British National Corpus. A freely available small subset of this huge collection of written texts.
Cambridge Dictionaries. Online look up in any of five dictionaries.
Merriam-Webster. Search the Merriam-Webster Collegiate Dictionary.
OneLook Dictionaries. Gives access to several hundred online dictionaries.
Oxford English Dictionary online. An expensive subscription service, but some background documents and a Word of the Day are available free. UK residents with a library card get free access.
YourDictionary.com. Dictionaries for 200+ languages.
Visual Thesaurus. A unique way to visualise links between words. The site also has many blogs and other departments.
Australian National Dictionary Centre . Compilers of the Australian National Dictionary and other works.
Scottish National Dictionary Association. Publishers of the standard dictionary of modern Scots.
Dictionary Unit for South African English. At Rhodes University. Includes articles on South African English.
The American Language. The Second Edition of H L Mencken’s classic is online at Bartleby.com.
British Library Language & Literature centre. Among other themes are those on the changing language, English regional dialects and the history of dictionaries.
The Elements of Style. The original 1918 first edition of this famous work by William Strunk. Now principally of historical interest.
Ask a Linguist. An online questions and answers service.
The Eggcorn Database. Eggcorns are unusual English spellings caused by writers trying to make sense of unfamiliar words, such as “reckless” turning into “wreckless”.
FAQs About Linguistics. By Professor John Lawler.
Linguist List home page. Mailing lists and archives.
Phonetics and Linguistics. At University College, London.
A Word A Day. Sent out every weekday.
dictionary.com. Word of the Day
Merriam-Webster’s Word of the Day. A daily mailing
American Dialect Society. Includes a searchable archive.
Dictionary of American Regional English. A major dictionary project, now on its last volume.
Estuary English. Documents and links at University College, London.
Scots Online. An introduction to the spoken and written Scots language.
Arnold Zwicky’s blog. By Arnold Zwicky, Visiting Professor of Linguistics at Stanford University.
DCBlog. David Crystal’s observations on English.
Language Log. Several professional linguists, including Geoffrey Pullum and Mark Liberman, comment on language of the moment.
Oxford Etymologist. American etymologist Anatoly Liberman writes a weekly column on the origins of words.
Separated By A Common Language. Observations on British and American English by an American linguist in the UK.
Take Our Word For It. Updated weekly.
Vocabula Review. A monthly magazine on language.
Web of Language. A regular blog by Dennis Baron, professor of English and linguistics at the University of Illinois.
Word Detective. Updated fortnightly.
Dictionary of Slang. Slang from a British perspective. Updated monthly.
Double-Tongued Word Wrester. Grant Barrett records slang and neologisms from an American perspective.
The Jargon File. A comprehensive collection of terms relating to computing. The original online source from which the printed New Hacker’s Dictionary was compiled.
Maledicta. A learned discussion of multilingual insults, including obscenities. Not for the faint-hearted or rigid of mind.
Online Slang Dictionary. A large selection, mainly user-contributed.
The Septic's Companion: A British Slang Dictionary. Formerly The English-to-American Dictionary. A large collection of words in colloquial British English that are likely to confuse Americans in particular.
The Urban Dictionary. A user-compiled slang dictionary. Often useful, but entries need to be approached with caution.
Variety Slanguage Dictionary. The magazine is renowned for its linguistic inventiveness, such as “ankle” meaning to leave a job. The magazine has posted this glossary of its principal inventions.
Common Errors in English. Paul Brians’ site.
The Guardian Style Guide. The style guide for the British newspapers The Observer and the Guardian.
Guide to Grammar and Style. By Jack Lynch. An online style guide with information designed originally for business writers.
US Government Printing Office Style Manual. Viewable as text or downloadable PDF files.
alt.usage.english. A vast archive of material from this very active Usenet newsgroup.
A Way with Words. A lively American radio programme from PBS, conducted by Martha Barnette and Grant Barrett.
Banished Word List. A list of words which, according to Lake Superior State University, should be banned from the language through overuse or misuse. A slight site, but thought-provoking.
Martha Barnette’s Fun Words. An archive of some less common words that are great fun to discover.
BuzzWhack. Dedicated to demystifying buzzwords such as “Very Low Food Security”, meaning poor and hungry.
e-editor. A British site for copyeditors, “mainly aimed at helping and supporting e-editors and non-news editing staff everywhere”.
Focusing On Words. Particularly the Latin and Greek elements used in English. Mailing list.
Fun With Words. Daniel Austin's wordplay site, including word puzzles and games. The Funny Signs gallery is worth a visit alone.
Luciferous Logolepsy. A collection of over 9,000 obscure English words.
Rhetoric. Ross Scaife tells you more than you ever thought you needed to know about rhetoric, in alphabetical order from Anacoluthon to Zeugma.
Richard Lederer’s Verbivore Page. The web site woven for wordaholics, logolepts, and verbivores
Dave Wilton’s Etymology Page. A collection of short articles on the origins of words in English.
Words and Stuff. Jed Hartman’s language columns, on a great variety of subjects.
Word Wizard. Your questions answered, a selection of new words provided, plus “snappy quotes and elegant insults”, competitions, Fancy Word Parties and Lexicographer’s Club.