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.
Counterhegemony
Counter-hegemony refers to attempts to critique or dismantle hegemonic power. In other words, it is a confrontation and/or opposition to existing status quo and its legitimacy in politics, but can also be observed in various other spheres of life, such as history, media, music, etc. Neo-Gramscian theorist Nicola Pratt (2004) has described counter-hegemony as "a creation of an alternative hegemony on the terrain of civil society in preparation for political change".