Notgeld (German for "emergency money" or "necessity money" ; "monnaie de nécessité" in French) is the name of money issued by an institution not authorized for money emission. This occurs usually when money is not available from the central bank. The best known emergency money emissions occurred in Germany and Austria around the end of the First World War, which is why the German term is used. Issuing institutions could be e.g. town savings banks, municipalities, private and state-owned firms. It was therefore not legal tender, but rather a mutually-accepted means of payment in a particular locale or site. Notgeld is different from occupation money that is issued by an occupying army during a war.

Notgeld was mainly issued in the form of (paper) banknotes. Sometimes other forms were used, as well: coins, leather, silk, linen, stamps, aluminium foil, coal, and porcelain; there are also reports of elemental sulfur being used, as well as all sorts of re-used paper and carton material (e.g. playing cards). These pieces made from playing cards are extremely rare and are known as Spielkarten, the German word for "playing card".

Read more about Notgeld:  Notgeld During The Great War, Notgeld During The German Hyperinflation, In Sweden 1715–1719