Have you heard of the Steinlaus? It’s a German word that translates to “stone louse”. And according to a German medical dictionary, it’s a rodent-like mite that can be used to break down kidney stones. Since the word was first listed in the dictionary in 1983, research on the stone louse has progressed rapidly and homeopaths have adopted it as a remedy. . There’s only one problem: it doesn’t EXIST.

So why would the compilers of a dictionary deliberately include a false entry? For copyright purposes. According to New Scientist magazine, dictionary editors face a huge problem when it comes to protecting their work. They invest a lot of time, money and man-power compiling a list of facts, which are then easily copied – especially from digital editions. And a fake entry is the perfect way to detect large-scale unauthorized copying of such a collection. If it turns up in someone else’s dictionary, that’s some pretty strong evidence of plagiarism.

And dictionary compilers aren’t the only ones who use this trap. Map-makers do it, too. In the 1930s, U.S. map-maker Esso marked the fictitious town of Agloe at the intersection of two dirt tracks on its maps of the Catskill Mountains in New York. Years later, Agloe turned up on a map from rivals Rand McNally. But here’s where the catch-22 of these fake entries come in: Rand McNally managed to prove that county officials had supplied them with the name. You see, someone had built a general store at the intersection and called it “Agloe” - because that’s what was marked on his Esso map! So the phony word had managed to make it’ sway into reality!

Still, these traps are pretty useful at nailing plagiarists. So when you’re scanning the dictionary or a roadmap, don’t believe everything you READ.