Zzxjoanw is a famous fictitious entry which fooled logologists for many years. In 1903, author Rupert Hughes published The Musical Guide, including a section containing a "pronouncing and defining dictionary of terms, instruments, etc". The "dictionary" occupied 252 pages, explaining the meanings and pronunciations of the German, Italian and other non-English words found in the terminology of classical music. As the very end of the dictionary, immediately after an entry for "zymbel" (German for cymbal), Hughes added the following definition:

zzxjoanw (shaw). Maori. 1. Drum. 2. Fife. 3. Conclusion.

More information on the Wikipedia page [1], and the original entry can be found on the Googlebooks page [2]