Credo, Gale, and Oxford offer reference collections that let you cross-search many dictionaries and encyclopedias at once!
Dictionaries, encyclopedias, etc. from a variety of sources.
Online reference works from a variety of publishers.
Reference books by Oxford University Press, including the Oxford Digital Reference Shelf.
Full text literary criticism, overviews and reviews of literary works, author biographies in all disciplines, from all times and geographic areas.
Reference books by Oxford University Press, including the Oxford Digital Reference Shelf.
The largest and most comprehensive English dictionary. Provides a history of most words through examples of usage in written works of literature. Print version available in Clemens Oversize PE1625 .O87 1989
Not sure if it's okay to use Wikipedia or a web search as a starting point for your research? Check with your instructor or a librarian!
For an overview of the issue, check out Wikipedia's Citing Wikipedia article!