West Germany (German: Westdeutschland) was the part of Germany that was occupied by the 3 Great Powers after World War II: the United Kingdom, United States and France. About three quarters of Germany was included in West Germany which existed from 1949 till reunification in the late 1980's. The other quarter of Germany was occupied by another Great Power - the Soviet Union, and was a communist state known as East Germany or the DDR. During the later part of this time the Berlin Wall separated the two parts of Germany.
West Germany was a federal Democracy with Bonn as its capital. West Germany was also a founding member of the European Union. West Germany established a Social democratic economic system with a large welfare state and some degree of state intervention in the economy. This is referred to as the "Economic Miracle". Under this system West Germany became the most powerful economy in Europe.
After communism collapsed in Central Europe both parts of Germany chose democratically to reunite and West Germany ceased to exist. The part of united Germany that was West Germany is still sometimes called Former West Germany. With time, the differences between former West Germany and Former East Germany will steadily decrease. The use of the terms East Germany and West Germany is very controversial and considered offensive and provocative.