Zyzzogeton is a genus of South American leaf hoppers. South America South America is a continent crossed by the equator, with most of its area in the Southern Hemisphere. ...
The word is known for being the last word in the Webster's Third New International Unabridged Dictionary, released in September 1961. It is still present in Merriam-Webster Unabridged dictionaries. 1888 advertisement for Websters Dictionary Websters Dictionary is a common title given to English language dictionaries in the United States, deriving its name from American lexicographer Noah Webster. ... 1961 was a common year starting on Sunday (link will take you to calendar). ... Merriam-Webster, originally known as the G. & C. Merriam Company of Springfield, Massachusetts, is a United States company that publishes reference books, especially dictionaries that are descendants of Noah Websters An American Dictionary of the English Language (1828). ...
After about a decade of preparation, Merriam issued the entirely new Webster's Third New International Dictionary, Unabridged (familiarly known as Webster's Third,) in September 1961, edited by Philip Babcock Gove and containing over 450,000 entries, including over 50,000 new words and as many new senses for existing words.
The final definition, zyzzogeton, was written on October 17, 1960, the final etymology was done on October 26, and the final pronunciation was done on November 9.
The book was printed by the Riverside Press in Cambridge, Massachusetts.
The last word is, according to the unabridged dictionary, zyzzogeton.
These are tough criteria, although maybe some obscure back-formation or other alteration of zyzzogeton might manage.
according to MY dictionary the last word is zyzzyva...which obviously would come after zyzzogeton hahahaah hahahahahah....*evil grin.....if you don't beleive me the definition is: any of various tropical American weevils of the genus zyzzyva, often destructive to plants.