The American Century is a term sometimes used for the 20th century.
It is based on the idea of United States dominance of much of the 20th century, beginning with the Spanish-American War and the pivotal roles played by the United States in World War I and World War II, continuing on through the Cold War status of the United States as one of the world's two superpowers, and ending with the role of the United States as sole superpower (some say hegemon or hyperpower) in the 1990s. It refers not only to the political influence of the United States, but also its economic influence, as many states around the world would, over the course of the 20th century, adopt the economic policies of the Washington Consensus.
Critics of the term regard it as overemphasizing the role played by the United States on the world stage.
The name of the thinktank Project for the New American Century implicitly suggests that the 20th century was an American Century and that a goal of the thinktank is to make the 21st century an American Century as well.
Journalist Harold Evans wrote a book entitled The American Century.
See also