When asked “What is the first word listed in a dictionary?” most people correctly answer correctly: A (used commonly as a noun, article, or preposition). The followup question is not so easily answered: “What is the last word in a dictionary?”
That distinction belongs to Zyzzyva. Nope — it isn’t an illness; nor is it one of those alphabet-soup appellations belonging to a startup technology or social media company (of course, it will only be a matter of time…). The Zyzzyva (pronounced “ziz – uh – vuh”) is the genus of the South American weevil that is destructive to plants. The Zyzzyva is a beetle with a short beak, not much longer than an ant. The weevil was discovered in Brazil by entomologist Thomas Casey, Jr. in 1922. It is not certain how Casey arrived at this curious word, however one entomologist has speculated that this name would ensure that it would be memorable since it would be listed last in field guides — not to mention just about every dictionary.
For further reading: American Heritage Dictionary of the English Language (5th Edition), Houghton Mifflin Harcourt (2011). http://www.wikipedia.com.