MERRIAM-WEBSTER'S
COLLEGIATE DICTIONARY 

11th Edition, 2020. Available practically everywhere. A "collegiate" dictionary provides especially good etymologies of words (including Greek and Latin roots words). Paperback dictionaries typically do not. You will never have to go through life not knowing a word's meaning with this dictionary. It's a good investment.











THE CONCISE COLUMBIA
ENCYCLOPEDIA 

From Columbia University. Available practically everywhere. This one-volume encyclopedia provides concise explanations of the most important events in history. It is easy to use and indispensable. Find it used somewhere at a low price.











A DICTIONARY OF
MODERN ENGLISH USAGE

By H. W. Fowler. Available practically everywhere. This is the classic text on how to use the tricky words in English correctly. Find it used somewhere at a low price.










THE OXFORD ENGLISH DICTIONARY
ONLINE

From Oxford University. This is the largest dictionary in the world. It is a masterpiece of Western literature. It can be accessed with a subscription from one's own local library. Visit the OED website for instructions.

THE OXFORD
CLASSICAL DICTIONARY

From Oxford University. This contains expert, scholarly, and reliable definitions of the classical world. It can be expensive to buy in some places, but used versions can be found at a low price.











THE OXFORD DICTIONARY
OF LITERARY TERMS

From Oxford University. Available practically everywhere. For literature and writing students. The Penguin Dictionary of Literary Terms (by J. A. Cuddon) is also good.










THE MLA HANDBOOK
(9th Edition)

From The Modern Language Association. Available practically everywhere. The MLA guidlines for writing college research papers and other scholarly treatises are explained here.