The dominance of one social group over another, particularly with some form of consent by subordinate parties.
Hegemony is a concept that has been used to describe and explain the dominance of one social group over another, such that the ruling group or hegemon acquires some degree of consent from the subordinate, as opposed to dominance purely by force. It is used broadly to mean any kind of dominance, and narrowly to refer to specifically cultural and non-military dominance, as opposed to the related notions of empirialism.
Researchers use hegemony to explain how dominant groups or individuals can maintain their power -- the capacity of dominant classes to persuade subordinate ones to accept, adopt and internalize their values and norms.
Antonio Gramsci devised one of the best-known accounts of hegemony. His theory defined the State by a mixture of coercion and hegemony, between which he drew distinctions. According to Gramsci, hegemony consists of socio-political power that flows from enabling the "spontaneous consent" of the populace through intellectual and moral leadership or authority as employed by the subalterns of the State. The power of the hegemony is thus primarily through coercion and consent rather than armed force. Such conceptions are sometimes referred to as "cultural hegemony." It should be made clear that these 'subalterns of state' include entities like media, religious groups, education systems, and even entertainment, (like movies and music) that influence participants on certain issues, and help maintain the staus quo, whether that is the privelege of a race, or a governing body.
Joseph, Jonathan (2002), Hegemony: a realist analysis, New York: Routledge
Hegemony and Socialist Strategy, Ernesto Laclau and Chantal Mouffe