Source : Webster's Revised Unabridged Dictionary (1913)

Hegemony \He*gem`o*ny\, n. [Gr. ?, fr. ? guide, leader, fr. ? to
   go before.]
   Leadership; preponderant influence or authority; -- usually
   applied to the relation of a government or state to its
   neighbors or confederates. --Lieber.

Source : WordNet®

hegemony
     n : the domination of one state over its allies