Even though it’s an online class, do you have a way to ask your instructor questions? Ask him to recommend a book, then check Amazon.com to see if you can find a copy that is used, but gently worn. You’ll get your best value for your money that way.

If your instructor doesn’t have any titles to offer, check the catalog of your state agricultural school. Where I live, that would be Kansas State University; where my daughter lives, it would be Texas A&M. You probably know which university is the ag. school in your state.

Once you find the school’s online catalog, subject search “veterinary medicine — dictionaries” and see what titles are listed. Too many to chose from? Choose a few titles that look interesting, then call a local vet and ask him which one he would buy.

Once you know what you are looking for, go back to Amazon.com, or Barnes & Noble, or another online bookstore that connects you with used book sellers and see what you can find that is in your price range.

Still not sure? Ask your local library to interlibrary loan a copy so you can use it for a period of time (usually about 2 weeks) before you decide this is the one you want to buy. Then go back to the online book stores and buy the one you like.