Hegemony
In the 19th century, hegemony came to denote the "Social or cultural predominance or ascendancy; predominance by one group within a society or milieu". Later, it could be used to mean "a group or regime which exerts undue influence within a society". Also, it could be used for the geopolitical and the cultural predominance of one country over others, from which was derived "hegemonism", as in the idea that the Great Powers meant to establish European hegemony over Asia and Africa.
Polarity (international relations)
In “Command of the Commons: The Military Foundation of U.S. Hegemony,” Barry Posen focuses exclusively on U.S. military capabilities. A key to U.S. preeminence is “command of the commons—command of the sea, space, and air.” But command of the commons and the U.S. persistence in maintaining its near omnipresence raise important questions for U.S. strategy: “Even before the September 11 terrorist attacks, the foreign policy debate had narrowed to a dispute between primacy and selective engagement, between nationalist, unilateralist version of hegemony, and a liberal, multilateral version of hegemony.” U.S. command of the commons, Posen argues, provides a strong case for selective engagement. Posen believes that the Bush Doctrine was problematic because it not only created unease among U.S. allies, but also caused “others to ally against the United States.” Securing the commons through selective engagement is a superior strategy because it is cost effective, secures U.S. interests, and makes the nearly omnipresent U.S. military tolerable because it provides security guarantees to other nations.