Dictionaries and Encyclopedias
While not as comprehensive as other sources, this is a good quick reference site from an authority in dictionary publishing.
OneLook is a meta-dictionary. Enter an English language word or acronym, and OneLook will search its index of over 900 general and special interest dictionaries for the definition.
Provides a variety of links to specialized subject dictionaries in many different areas.
A graphical dictionary/thesaurus that allows you to see the relations between words, concepts, and associations.
An online project that gives as much information as possible for words, such as images, statistics, pronounciation, and multple definitions.
Encyclopedia in development with the goal of having information about every single organism on Earth.
Authoritative online encyclopedia of mythology, folklore, and religion.
All the facts from the printed almanac, plus a dictionary and encyclopedia.