I pitched this article to Aquila children's magazine earlier this year. I think the magazine is really great. They don't talk down to their audience, they work with subject matter experts, they commission original illustrations, they like original takes on their monthly topics... I could go on. When they announced that they were looking for pieces for their upcoming Words issue, I thought "finally, a subject in which I'm an expert" and sent them my idea.

The subject of Lillian Virginia Mountweazel has fascinated me ever since I heard about her on The Allusionist podcast and I've been absolutely obsessed with meta-textual things like this since even earlier than that, reading A Series of Unfortunate Events as a child.

All that to say that, when the pitch was unsuccessful, I set about writing the piece anyway.

Don't believe one word

Next time you check the dictionary, check a second one just to be sure. Lexicographers, researchers and publishers have been known to add fake entries to their books...

esquivalience – n. the avoidance of one’s responsibilities

The New Oxford American Dictionary sent readers searching in 2005 when it revealed that one word in its 2,095 pages was fake. The word was eventually discovered by a journalist. But not before a rival dictionary made the mistake of adding esquivalience to its own pages.

Lillian Virginia Mountweazel – 1942-73, American photographer

The 1975 edition of the New Columbia Encyclopedia didn’t stop at words. Lillian Virginia Mountweazel was supposedly a celebrated photographer of New York City buses, Paris cemeteries and other unusual subjects. That is, until she was killed in an explosion while working for a magazine called Combustibles. Of course, Mountweazel never really existed. But her name has come to mean exactly what she was – a made-up entry in an encyclopedia or other reference book.

Agloe – a mountain town north of New York City

Mapmakers Otto Lindberg and Ernest Alpens added a fake town to their map of New York state, combining their initials to name it. But the strangest thing about Agloe is that it didn’t stay fake. Not long after, somebody decided that the town of Agloe was the perfect spot to open a shop. But with no other people around, the Agloe General Store went out of business quite quickly.

Why make up a word?

There are plenty of reasons to make up a word. It’s splendifying (a word I just made up for fun). But there aren’t so many reasons for putting a made-up word, or Mountweazel, in the dictionary. So, why did all these serious reference books do something so silly?

Lexicographers work very hard to find words, learn their meanings and write them down. And while none of them does it for the money, few want to do it for free. Samuel Johnson was paid £300,000 in today’s money to research and write his Dictionary of the English Language (and it cost the publishers even more to print copies). Mountweazels were originally meant as a way for publishers to protect their investment.

Think about it. If you wanted to publish a dictionary, encyclopedia or map but didn’t want to do any of the hard work, all you had to do was copy one from a rival, make a few small changes to cover your tracks and... Well, you’d be rich faster than you could say esquivalience.

It’s unlikely that this was a problem in Johnson’s day. But people had certainly caught on by the early 20th century. Another Mountweazel meant to catch out the competition appeared as early as 1903, in a book called the Music Lovers’ Encyclopedia. The book claimed that zzxjoanw was a Maori word for “drum” (even though the Maori alphabet doesn’t have the letters z, x or j) and “conclusion” (it was no coincidence that this was the last entry in the book). Lexicographers, researchers and their publishers have been adding made-up words to their works ever since.

What can you believe?

If your trust in dictionaries, encyclopedias and maps has been shaken, we apologise. But it’s a fair question: When so many of these books include fake entries, how can we believe a single word they say? Here’s our advice.

If it’s a word you’ve read elsewhere and you’re looking it up, the entry is reliable. If it’s a person or place you’ve heard about and you want to know more, trust your encyclopedia or map. Remember that you’re unlikely to find any of these fake words, people or places in the real world – only in certain books.

And if you’re browsing your reference books for fun... Well, first of all, we’d love to hear what you find. Second of all, it’s as simple as checking a second source when you’re in doubt. (This is a good habit even if you don’t suspect an entry of being fake.)