The best dictionary entry in history appeared in some editions of Brewer’s Dictionary of Phrase and Fable: “Zymurgist (noun). Brewer. The last word in dictionaries.”
Brewer’s Dictionary of Phrase and Fable is one of the most delightful reference works of the last couple of hundred years. Originally compiled by Ebenezer Cobham Brewer and published in 1870, it’s a collection of antique sayings and literary references ranging from the obvious (Sleeping Beauty) to the obscure (Myrmidons of the Law).
Its original purpose was probably to help readers navigate the sea of allusions in English books: it was common practice to make references to Classical texts, for example, as a kind of shorthand… but that shorthand only works if you actually understood the reference. Brewer’s dictionary helped the literary lost; it was the Google of its day.
It’s also wonderfully weird. As with many reference works written by a single author, the book makes funny choices about what is important or worth knowing. I’m a fan of the eclectic, and this is pretty much Peak Eclectic. (Because it was written in the 19th century CE, it’s also occasionally awful.)
This dictionary has been in print since 1870, and has been frequently revised – it’s up to the 20th edition now. At some point in all of these revisions (I suspect but cannot confirm that it was the 15th, revised by Adrian Room) a new entry appeared on the last page. And it’s perfect.
Zymurgist (noun). Brewer. The last word in dictionaries.
“Zymurgy” describes the process of making wine or beer. A zymurgist, therefore, is another name for a brewer. Because it begins with a zy, alphabetically there aren’t many words that would come after it in a dictionary (Sit down, you zzyzx fans!). Hence, “the last word in dictionaries.” And this entry appears in Brewer’s dictionary, itself “the last word in dictionaries.”
Amazing.
The Generalist Academy 
I have this book and I didn’t know that!