Supremacy is the state of being above all others in power. Air supremacy, naval supremacy, a struggle for supremacy.
In military use it is a defined step above superiority: superiority means you mostly control the sky and supremacy means the enemy cannot fly at all. The word also appears in the ugliest of political phrases, where it names a doctrine of racial rank.
1nounsupremacyThe state of being above all others in power.
“Rome and Carthage fought for supremacy in the western Mediterranean.”
supremacy is a state.
From supreme, from Latin supremus, highest, the superlative of superus, above.
From supreme + -acy (a variant of -cy). Compare with supremity and New Latin suprematia.
Etymology from Wiktionary, CC BY-SA