Etymology

Businessballs.com - Etymology of Clichés, Expressions and Words Etymology - English language terms and expressions.
http://www.businessballs.com/clichesorigins.htm

Taiwan Teacher - A new word or phrase posted every week giving you the meaning, origin and an example of the usage of the word or phrase.
http://www.geocities.com/athens/delphi/1979/trivia.html

Online Etymology Dictionary - History and evolution of more than 30,000 words, including slang and technical terms.
http://www.etymonline.com/

Roots of English - An etymological dictionary you can download by Prof. Eugene Cotter, Seton Hall University.
http://ablemedia.com/ctcweb/showcase/roots.html

Altaic Etymology - Online database version of the Altaic Etymological Dictionary by S. Starostin, A. Dybo and O. Mudrak.
http://starling.rinet.ru/cgi-bin/startq.cgi?flags=eygtnnl&root=config&basename=%5Cdata%5Calt%5Caltet

MooT - The game of grammar, semantics, and etymology. Play online the game that investigates the history and meaning of English words.
http://www.mootgame.com/

Word Sources - Includes a searchable database of Latin and Greek roots and affixes, a free newsletter, and links to other sites.
http://www.wordsources.info/

Word and Phrase Origins - Directory. Part of the Internet Public Library. Describes books and web sites that might be helpful. Offers a hint on how to use an ordinary search engine when looking for etymology.
http://www.ipl.org/div/pf/entry/48468

Dave Wilton's Etymology Page - Devoted to etymology of common words and slang phrases.
http://www.wordorigins.org/

Richard Lederer's Verbivore - Linguistic fun from, Richard Lederer, the best-selling author of The Word Circus and the new Sleeping Dogs Don't Lay, a helpful guide for grappling with vexing grammar questions.
http://www.verbivore.com/

Word Origins - This regularly updated page, provided by The Writer's Place, focuses on a word and its spelling, pronunciation, and derivation.
http://www.thewritersplace.com/writestuff/origins.htm

The Phrase Finder - The meanings and origins of thousands of English phrases and sayings. Also includes a discussion forum to ask a panel questions on the meaning and origin of phrases.
http://www.phrases.org.uk/

Word Origins and Meanings of Economic Terms - Click on a word and go right to a brief discussion of its origin.
http://www.louisville.edu/~bmhawo01/econpage/meanings.html

New York State Facts - The origins of New York State's county names.
http://www.dos.state.ny.us/kidsroom/nysfacts/counties.html

Exploring English Words - Exploring English words that are derived from Latin and Greek sources with etymologies and vocabulary activities.
http://www.wordexplorations.info

World Wide Words - Michael Quinion writes about International English from a British viewpoint. Hundreds of pages on the history, origins, evolution and idiosyncrasies of English, with features on new words and words in the news.
http://www.worldwidewords.org/

Sayings and Everyday Expressions - Your online source for the sayings and expressions you use everyday. Search for their meaning, history and origin, find sayings, expressions, phrases, quotations, cliches, unusual words, and wordplay.
http://users.tinyonline.co.uk/gswithenbank/sayindex.htm

Nautical Expressions in the Vernacular - Myriad expressions in everyday English have nautical origins. This web page lists expressions and definitions mentioned by listswains, members of the Patrick O'Brian Mailing List, also known as the Gunroom.
http://www.io.com/gibbonsb/words.words.words.html

A Comparative Dictionary of Indo-Aryan Languages - Online version of the indexes of R.L. Turner's 1962-1985 dictionary from the Digital Dictionaries of South Asia.
http://dsal.uchicago.edu/dictionaries/soas/

Etymologically Speaking - A list of some curious word origins.
http://www.westegg.com/etymology/

Words with Heathen Origins in the Scriptures - An etymological study of numerous words used in churches and Scriptures that have their origin in pagan religions.
http://www.innvista.com/culture/religion/bible/compare/heathen.htm

Etymologic - The brain-twisting etymology game.
http://www.etymologic.com/

Word Quests for Word Seekers - Searchable dictionary of word origins, organized in cross-referenced thematic lists by Latin and/or Greek roots. English entries are also defined.
http://www.wordquests.info

Etymology - Word origins and links.
http://members.tripod.com/~itsmagic/ETYMOLGY.HTML

American Dialect Society - A scholarly association dedicated to the study of the English language in North America.
http://www.americandialect.org/

languagehat.com - Erudite blog on word origins and definitions, with dozens of links to dictionaries, commentaries, linguistic reference sites, and personal favorites of the author.
http://www.languagehat.com/

English Language Roots: The Meanings of Word Prefixes, Suffixes and Syllables - Reference chart for Greek, Latin, and other roots of the English language. Understanding such roots can help guessing the meaning of words and creating neologisms or brand names.
http://www.prefixsuffix.com

The Word Detective - Words and language in a humorous vein. The online version of The Word Detective, a newspaper column answering readers' questions about words and language. Written by Evan Morris.
http://www.word-detective.com/

What's The Meaning of This? - The origins of quirky English words and phrases like "In like Flynn" and "blackmail."
http://www.rootsweb.ancestry.com/~genepool/meanings.htm

Focusing on Words - An advanced Latin-Greek-English vocabulary source of etymologies with thematic units of roots, prefixes, and suffixes, and vocabulary quizzes.
http://www.wordfocus.com/

Origin of Phrases - Categorized etymologies of phrases.
http://members.aol.com/MorelandC/Phrases.htm

Pandora's Word Box - Relates medical terminology to the humanities, offering a weekly overview with references to classical etymology.
http://pandorawordbox.com/

European Sayings & Idiomatic Expressions - Dedicated to gathering sayings and idioms and their translation/explanation from all over Europe. User contributions welcome.
http://sayings.jacomac.de/

Take Our Word for It - Weekly etymology magazine.
http://www.takeourword.com/

New Words In English - Neologisms and novel uses of words in English collected by members of the class Linguistics/English 215, Words in English: Structure, History and Use, taught by Suzanne Kemmer at Rice University.
http://www.owlnet.rice.edu/~ling215/NewWords/index.html

Oxford English Dictionary - Presents a word a day complete with pronunciation, spellings, etymology, quotations and date chart.
http://oed.com/cgi/display/wotd

Word Spy - Collection of recently coined words, existing words that have enjoyed a recent Renaissance, and older words that are now being used in new ways.
http://www.wordspy.com/