Notgeld
  
If the word “notgeld” sounds a little German, that’s because it is. It translates to “emergency money,” and it’s used in situations where the government is broke, the central bank is out of money, and people have to pay for stuff using other means.
This dire set of circumstances doesn’t occur very often, but it has happened. Take World War I, for example. After the war, Germany and Austria found themselves in a bit of a financial pickle. To put it succinctly, they were up broke creek without a paddle. As a result, some local banks and private companies started issuing their own currencies, called “notgeld.” These currencies weren’t actually legal tender, but folks needed to buy stuff, so a lot of local vendors started accepting them anyway. A lot of times, notgeld was issued in banknote form, but there were others made out of leather, wood, porcelain, and even playing cards.
Today, the term “notgeld” is used to refer to any money issued by an institution that doesn’t have the authority to do so. And no, this doesn’t mean Monopoly money is notgeld. It’s only used to describe situations in which the government can’t back its country’s currency, so small banks and organizations create temporary (and often localized) payment methods.