Dictionaries

Merriam-Webster Word Central
http://wordcentral.com/
Includes: student dictionary, rhyming dictionary, verse composer, links to other dictionaries in the Teacher's Lounge.
Merriam-Webster On-Line
http://www.m-w.com/
Adult version. Includes word of the day and word games.
Encarta World English Dictionary
http://encarta.msn.com/encnet/features/dictionary/dictionaryhome.aspx
Includes sound clips of the words.
YourDictionary.com
http://www.yourdictionary.com/
Specialty dictionaries, Thesauri, Language dictionaries, and more...
The Free Dictionary
http://www.thefreedictionary.com/
Cambridge Dictionaries Online
http://dictionary.cambridge.org/
The Visual Dictionary
http://infovisual.info/
Quick searches for terms: in biology- vegitation and animal, human body, music, transport, and clothing.
3D Dictionary
http://www.maran.com/dictionary/index.html
Glossary of computer-based terms
Dictionary of Difficult Words
http://www.tiscali.co.uk/reference/dictionaries/difficultwords/
Challenge your students to enrich their vocabulary.
RhymeZone
http://www.rhymezone.com/
Search for rhyming words, synonyms, antonyms, definitions, related words, similar sounding words, homophones, match consonants, match letters, find similar spellings, pictures, Shakespeare, quotations.
A Handbook of Rhetorical Devices
http://www.virtualsalt.com/rhetoric.htm
Explanations with examples.
A Glossary of Rhetorical Terms with Examples
http://www.uky.edu/ArtsSciences/Classics/rhetoric.html
A Glossary of Literary Terms
http://www.virtualsalt.com/litterms.htm
Fun With Words
http://rinkworks.com/words/
You can look up: collective nouns, proprietary eponyms, contronyms, heteronyms, unusual word forms, negatives without positives, numbers, word oddities, commonly misspelled words, commonly mispronounced words, commonly confused words, phone number words, word frequencies.
Fun With Words
http://fun-with-words.com/
The Wordplay Website: Anagrams, Palindromes, Tongue Twisters, Etymology, Word Puzzles, Spoonerisms, Oxymora (Oxymorons), Malapropisms, Pangrams, Mnemonics, Acronyms, Cockney Rhyming Slang.
Multi-Volume Glossary
http://www.ucmp.berkeley.edu/glossary/glossary.html
A multi-volume, multimedia virtual glossary for Phylogenetics, Geology, Biochemistry, Cell Biology, Ecology, Life History, Zoology and Botany.
A.Word.A.Day
http://www.wordsmith.org/awad/
Visit daily to learn a new word a day. You can also subscribe to the service.
Word Origins and Word Myths
http://www.wordorigins.org/
Etymology explored on this site.
The Word Detective
http://www.word-detective.com/
Newspaper columns answering questions about the origins of words.
Level: Senior, Adult
ODLIS: On-Line Dictionary of Library and Information Science
http://www.wcsu.edu/library/odlis.html
Lists print and non-print, computer and, library automation terminology.
Math Glossary
http://www.hbschool.com/glossary/math/index.html
Glossary of math terms sorted by grade.
A Maths Dictionary for Kids
http://www.amathsdictionaryforkids.com/
Definitions of math terms with examples and activities.
Sacred Hall of Computer and Internet Terms and Acronyms
http://www.pchell.com/acronyms/index.shtml
A guide to the most common computer terms with explanations of what they mean.
Science Glossary of Terms
http://nobel.scas.bcit.ca/resource/glossary/a-c.htm
Alphabetical list of definitions for scientists with links to further explanations.
Entomology Image Gallery
http://www.ent.iastate.edu/imagegallery/
Images of: beetles, lice, butterflies, moths, caterpillars, cicadas, leafhoppers, flies, mosquitoes, ticks, grasshoppers, crickets, true bugs, plant diseases.