Dictionaries, Encyclopedias, etc...

Credo Reference - A database of some 400 dictionaries, encyclopedias, and other reference sources on all subjects.

Dictionaries

Abbreviations.com
Merriam-Webster Online
OneLook Dictionaries
Oxford English Dictionary (OED)*

ARTFL Project ROGET'S Thesaurus Search Form
Wordsmyth: The Educational Dictionary-Thesaurus

The WWW Acronym and Abbreviation Server
Free On-line Dictionary of Computing

Encyclopedias

Information Please---Almanac, dictionary, encyclopedia, etc.

Quotations

Bartlett's Familiar Quotations
Famous Quotes and Authors
Quoteland

* restricted to use on the Truman State University network.