In economics, a
monetary union[?] is a situation where several countries have agreed to share a single currency between them.
European Monetary Union (EMU) was the proposal to establish such a single currency between the member states of the
European Union. That single currency has now come into existence, see
euro for more information.
EMU is also used as an abbreviation for economic and monetary union. European Monetary Union is an example of an economic and monetary union.