Superpower is a term used to describe a state with a dominant position, which is characterised by its extensive ability to exert influence or project power on a global scale. This is done through the combined-means of technological, cultural, military and economic strength, as well as diplomatic international relations and soft power influence. Traditionally, superpowers are preeminent among the great powers.
The term was first applied post-war to the British Empire, the United States and the Soviet Union. However, after the end of World War II and the Suez Crisis in 1956, the United Kingdom's status as a superpower was greatly diminished, leaving just the United States and Soviet Union as superpowers. For the duration of the Cold War the United States and the Soviet Union came to be generally regarded as the two remaining superpowers, dominating world affairs. At the end of the Cold War and the dissolution of the Soviet Union in 1991, only the United States appeared to fulfill the criteria of being a world superpower.
Alice Lyman Miller defines a superpower as "a country that has the capacity to project dominating power and influence anywhere in the world, and sometimes, in more than one region of the globe at a time, and so may plausibly attain the status of global hegemony."
There have been many attempts by historians to apply the term 'superpower' to a variety of past entities. However, since even the most powerful empires of old had little to no means to exert influence over very long distances, labeling them as such is complicated.
No agreed definition of what is a 'superpower' exists, and may differ between sources. However, a fundamental characteristic that is consistent with all definitions of a superpower is a nation or state that has mastered the seven dimensions of state power; geography, population, economy, resources, military, diplomacy and national identity.