Single market of the European Union and participating non-EU countries
The European single market, also known as the European internal market or the European common market, is the single market comprising mainly the 27 member states of the European Union (EU). With certain exceptions, it also comprises Iceland, Liechtenstein, Norway (through the Agreement on the European Economic Area), and Switzerland (through sectoral treaties). The single market seeks to guarantee the free movement of goods, capital, services, and people, known collectively as the "four freedoms".
https://en.wikipedia.org/wiki/European_single_market