mule
n.— « In the parlance of numismatists, a “mule” is “a coin or note with a mismatched obverse and reverse.” This may mean different types, different denominations, or even different countries. It is an exceptionally rare error, and specimens of this type are exceptionally prized by collectors.» —“Excessively Rare Lincoln Cent/Dime “Mule” to be Offered at Auction!” in Dallas, Texas News-Antique.com Apr. 3, 2006. (source: Double-Tongued Dictionary)
Further reading
The words tough, through, and dough all end in O-U-G-H. So why don’t they rhyme? A lively new book addresses the many quirks of English by explaining the history of words and phrases. And: have you ever been in a situation where a group makes...
When there’s no evening meal planned at home, what do you call that scramble to cobble together your own dinner? Some people apply acronyms like YOYO — “you’re on your own” — or CORN, for “Clean Out your Refrigerator...