The Oxford Thesaurus An A-Z Dictionary of Synonyms - supremacy n.

1) transcendency, pre-eminence, superiority, ascendancy, excellence, primacy, peerlessness, matchlessness, incomparability, inimitability: Colonialism depends on military supremacy. 2) sovereignty, dominion, sway, mastery, control, dominance, (supreme or absolute) rule or authority, autarchy, omnipotence, hegemony: They maintained their supremacy over the Iberian peninsula for centuries.