Free On-line Dictionary of Computing
- A searchable dictionary of terms from computing and related fields.
- http://foldoc.org/

Giraffian Children's Picture Dictionary
- A collection of illustrated words and concepts, aimed at children in preschool or early primary years.
- http://www.giraffian.com/pictionary/

Online Dictionary
- Find definitions of words using this online dictionary from AOL's Research and Learn channel.
- http://reference.aol.com/dictionary

Churchman Dictionary
- Lookup a definition in the search bar or by first letter. Includes a "word of the day".
- http://dictionary.oxid.ro/

Alcwin.org
- Site listing several types of dictionaries related to the sciences.
- http://www.alcwin.org

Pidic.com
- An online picture dictionary with thousands of images
- http://www.pidic.com/

Tech Terms Computer Dictionary
- A searchable dictionary of computer terms with definitions explained in simple language.
- http://www.techterms.org

Biographical Dictionary
- Read about more than 28,000 notable men and women from history. Search by names, dates, professions, achievements, and more.
- http://s9.com/

InfoVisual
- Thematic visual dictionary that focuses on learning through images. Concise definitions within the fields of vegetal biology, animal biology, human anatomy, and transportation.
- http://www.infovisual.info/

MSN Encarta Dictionary
- Online dictionary with over 100,000 entries, definitions, and pronunciations.
- http://encarta.msn.com/encnet/features/dictionary/dictionaryhome.aspx

eLook Dictionary
- Provides definitions, synonyms, and related words.
- http://www.elook.org/dictionary/

WebDictionary.co.uk
- Online dictionary and reference website.
- http://www.webdictionary.co.uk

Ice Phoenix Vocab Project
- Downloadable program that looks up entire lists of vocabulary words.
- http://iphoenix.sourceforge.net/

wordIQ
- Search on several different dictionaries, an encyclopedia, and the web.
- http://www.wordiq.com/

NetLingo Dictionary
- Provides a glossary of Internet jargon and acronyms.
- http://www.netlingo.com/

Terminology Collection: Online Dictionaries
- Glossaries for several languages and for specialized fields from the University of Vaasa, Finland.
- http://www.uwasa.fi/comm/termino/collect/

OneLook Dictionary Search
- Type in a word and search many dictionaries at once. Also has a reverse dictionary and translations.
- http://www.onelook.com/

RhymeZone
- Online rhyming dictionary. Search for a word and get a list of potential words that rhyme in addition to a definition.
- http://www.rhymezone.com/

Dictionary.com
- Online English dictionary, thesaurus and reference guide. Includes word games, online translator, and word of the day feature.
- http://dictionary.reference.com/

The Internet Picture Dictionary
- Free, online multilingual picture dictionary with interactive activities for English, French, German, Spanish, Italian and ESL learners.
- http://www.pdictionary.com/

PSEUDOdictionary
- Defines everyday words including slang, webspeak, and colloquialisms.
- http://www.pseudodictionary.com/

Fact Monster
- An online dictionary with definitions of more than 125,000 words and links to other related student tools.
- http://www.factmonster.com/dictionary.html

ArtLex
- Dictionary of visual art defines more than 3,500 art-related terms. Also includes a comprehensive collection of artwork and famous quotes.
- http://www.artlex.com/

DinoDictionary.com
- Features profiles of over 300 known dinosaurs along with pronunciations of their names.
- http://www.dinodictionary.com/

The Skeptic's Dictionary
- Definitions and essays on occult, paranormal, and supernatural ideas and practices from the point of view of someone who is a sceptic, that is, does not believe in these things.
- http://www.skepdic.com/

Webopedia
- Definitions of many computer-related terms, from hardware to the internet.
- http://www.webopedia.com/

The American Heritage Dictionary of the English Language
- Contains over 90,000 entries, including 70,000 audio word pronunciations.
- http://www.bartleby.com/61/

Little Explorers
- Picture dictionary gives definitions, pictures, and Internet links for over 2,350 entries. Includes translations for English to and from Dutch, French, Spanish, and more.
- http://www.enchantedlearning.com/Dictionary.html

Wordsmyth
- A dictionary and thesaurus in one. Also gives parts of speech and examples for more than 50,000 words.
- http://www.wordsmyth.net/