Books:
Endangered Words: A Collection of Rare Gems for Book Lovers
by Simon Hertnon
Rare Words and Ways to Master Their Meanings: 500 Arcane but Useful Words for Language Lovers
by Jan Leighton and Hallie Leighton
Rare Words II and Ways to Master Their Meanings: 500 More Unusual Selections, Some with Poetic Confections for Gleaning Their Meaning
by Jan Leighton
A Cure For The Common Word: Remedy Your Tired Vocabulary with 3,000 + Vibrant Alternatives to the Most Overused Words
by K. D. Sullivan
The Grand Panjandrum: And 1,999 Other Rare, Useful, and Delightful Words and Expressions
by J. N. Hook
The Word Lover’s Dictionary: Unusual, Obscure, and Preposterous Words
by Josefa Heifetz
The Oxford Dictionary of English Etymology
by C.T. Onions, G. W. S. Friedrichsen and R. W. Burchfield
The Barnhart Dictionary of Etymology
by Robert K. Barnhart and Sol Steinmetz
Websites
http://www.merriam-webster.com/
http://oxforddictionaries.com/
http://dictionary.cambridge.org/
http://www.macmillandictionary.com/
http://dictionary.reference.com/
