WordCentral.com [ Kids/Teens ] - Merriam-Webster's site for kids has a student dictionary, Daily Buzzword, and interactive word games. Includes homework help and lesson plans for parents and teachers.
The American Heritage Dictionary of the English Language [ Kids/Teens/Mature Teens ] - Contains over 90,000 entries, including 70,000 audio word pronunciations.
ArtLex [ Teens/Mature Teens ] - Dictionary of visual art defines more than 3,500 art-related terms. Also includes a comprehensive collection of artwork and famous quotes.
Biographical Dictionary [ Kids/Teens/Mature Teens ] - Read about more than 28,000 notable men and women from history. Search by names, dates, professions, achievements, and more.
Dictionary.com [ Kids/Teens/Mature Teens ] - Online English dictionary, thesaurus and reference guide. Includes word games, online translator, and word of the day feature.
DinoDictionary.com [ Kids/Teens/Mature Teens ] - Features profiles of over 300 known dinosaurs along with pronunciations of their names.
eLook Dictionary [ Kids/Teens ] - Provides definitions, synonyms, and related words.
Fact Monster [ Teens/Mature Teens ] - An online dictionary with definitions of more than 125,000 words.
Free On-line Dictionary of Computing [ Kids/Teens/Mature Teens ] - A searchable dictionary of terms from computing and related fields.
Giant Picture Dictionary [ Kids/Teens ] - Free online picture dictionary. Includes pictures representing both concrete and abstract concepts.
Ice Phoenix Vocab Project [ Teens/Mature Teens ] - Downloadable program that looks up entire lists of vocabulary words.
InfoVisual - Thematic visual dictionary by Bernard Déry, to learn by way of image. Concise definitions within the fields of vegetal biology, animal biology, and human anatomy.
The Internet Picture Dictionary [ Kids/Teens/Mature Teens ] - Free, online multilingual picture dictionary with interactive activities for English, French, German, Spanish, Italian and ESL learners.
Little Explorers [ Kids ] - 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.
MSN Encarta Dictionary [ Kids/Teens/Mature Teens ] - Online dictionary with over 100,000 entries, definitions, and pronunciations.
NetLingo Dictionary [ Teens/Mature Teens ] - Provides a glossary of Internet jargon and acronyms.
OneLook Dictionary Search [ Kids/Teens/Mature Teens ] - Type in a word and search many dictionaries at once. Also has a reverse dictionary.
PSEUDOdictionary [ Teens/Mature Teens ] - Defines everyday words including slang, webspeak, and colloquialisms.
Realdictionary.com [ Kids/Teens/Mature Teens ] - Features search to locate words by initial letters and numbers.
RhymeZone [ Kids/Teens/Mature Teens ] - Online rhyming dictionary. Search for a word and get a list of potential words that rhyme in addition to a definition.
The Skeptic's Dictionary [ Teens/Mature Teens ] - 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.
Tech Terms Computer Dictionary [ Mature Teens ] - A searchable dictionary of computer terms with definitions explained in simple language.
Terminology Collection: Online Dictionaries [ Teens/Mature Teens ] - Glossaries for several languages and for specialized fields from the University of Vaasa, Finland.
WebDictionary.co.uk [ Teens/Mature Teens ] - Online dictionary and reference website.
Webopedia [ Teens/Mature Teens ] - Definitions of many computer-related terms, from hardware to the internet.
wordIQ [ Teens/Mature Teens ] - Search on several different dictionaries, an encyclopedia, and the web.
Wordsmyth [ Kids/Teens/Mature Teens ] - A dictionary and thesaurus in one. Also gives parts of speech and examples for more than 50,000 words.