In the days immediately following WWII, the country of Germany and the city of Berlin were divided into four parts. Each part was controlled by one of the Allied powers from the war. These were the USSR, France, Great Britain, and the US.
Very soon after that, the last three of these powers started to cooperate in the administration of their zones. The Soviet Union did not cooperate with the other powers and was alarmed by the growing cooperation between the three. The Soviets did not want a unified West Germany. To try to pressure the West into giving up their plants to create a unified West Germany (and a unified West Berlin), the Soviets blockaded Berlin. This led to the Berlin Airlift.
A few months after the end of the blockade and airlift, the three Western powers formally united their zones. This created the country of West German and the city of West Berlin. This means that Germany and Berlin after the airlift were divided into two parts. There was West Germany and West Berlin, which had been the French, British and American zones, and East Germany and East Berlin, which had been the Soviet zone.