Hegemonic

Of or relating to dominance, especially of one state, group, or set of ideas over others; preponderant in influence.

From Greek 'hegemon' (leader), giving 'hegemonia' (leadership). Antonio Gramsci's 20th-century theory extended the term from political to cultural and ideological dominance.

"The hegemonic position of US dollar settlement in oil trade is being tested as Russia, Iran, and Venezuela increasingly invoice in rupees, yuan, and dirhams for Indian crude purchases."