The European Single Market is an agreement on the path to economic integration within the then European Communities (EC) that entered into force in 1993. It includes the EU Member States as well as Iceland, Norway, Liechtenstein, and Switzerland. The agreement includes four fundamental freedoms: free movement of workers, free movement of goods, free movement of services, and free movement of capital and payments.

Source: Bundeszentrale für politische Bildung, edited (only available in German)