Reference
These links will take you to sites that offer general reference tools.
http://www.chass.utoronto.ca/~cpercy/hell/
A reference site about the History of English, with other interesting reference materials.
http://en.wikipedia.org/wiki/History_of_the_English_Language
Wikipedia's description of the history and development of the English Language, with a number of useful cross-references.
http://www.ipl.org/
The Internet Public Library gives you and your students access to hundreds of reference materials from atlases to writing guides, all at the click of a button.
http://www.encyclopedia.com
An Internet encyclopaedia with over 14,000 articles and references.
Find out more about the words in the dictionary by using this resource. One of the most useful features is the cross-referencing which gives you the opportunity to explore meanings and the etymology of words in far more detail.