English and American Literature 

• The Concise Oxford Dictionary of Literary Terms (2nd ed., 2001)
• The John Hopkins Guide to Literary Theory & Criticism (rev. ed., 2004)
• Princeton Encyclopedia of Poetry and Poetics (1993) (Select this title from the Publication menu.)
• Routledge Encyclopedia of Philosophy
• Cambridge Collections Online: Cambridge Companions to Literature and Classics
• Oxford Reference: Literature              
  
• Cambridge Histories Online: Literary Studies

• Oxford English Dictionary
• Merriam-Webster Online
• The American Heritage Dictionary of the English Language (Credo Reference)
• Directory of Dictionaries available through Credo Reference
• Wordnik
• Urban Dictionary

In general, check the first floor reference center starting at PE 1580 and you will find books on word histories. The following are digital texts focused on etymology:

• The Concise Oxford Dictionary of English Etymology
• The Oxford Dictionary of Word Histories
• The Cassell Dictionary of Word Histories