The Oxford English Dictionary (OED) attempts to chronicle the origin and use of words in the English language. Important features include quotations showing uses of words in different time periods, extensive etymologies and word histories, and a program of regular, continuing revision. This is the largest English dictionary in both number of words defined and information given for each word.
You can find print and ebooks using the library catalog. If you'd like to browse Shakespeare books on the second floor of King, you might try the call number range PR2700-PR3100.