A revolution refers to any social, economic, or political upheaval and change. Revolutions may be violent (French Revolution), or peaceful (Glorious Revolution). Revolutions sometimes consist of independence movements (American Revolution), and at other times civil wars (Russian Revolution).
Karl Marx, the father of modern communism, believed that revolutions were inevitable and that the underclass would revolt against the ruling class. Marx's ideas were discredited with the collapse of the Soviet Union and a general rise in living conditions throughout the democratic world.
In astronomy, a revolution refers to a planetary object completing a full orbit. Because the word "revolution" comes from the Latin revolutio, meaning "turnaround", it can be seen to make sense in both contexts.