Oxford English Dictionary: We are fortunate to have quick and easy access to the largest historical dictionary ever published. The OED is designed to provide the history of meaning and use of almost all words in the English language, from 1100 through the late twentieth century, with illustrative quotations. The OED is restricted to UCM users, so if you are accessing it off campus, you’ll need to log on via the VPN. Instructions on how to do that are available here.
Samuel Johnson’s A Dictionary of the English Language (1755): Johnson’s was the first attempt at compiling a comprehensive dictionary of the English language. Not all entries have been digitized, but they are all viewable via the website’s “Page View”.