su·prem·a·cy \səˈpreməsē, süˈp-, -məsi sometimes -rēm-\noun (-es) Etymology:supreme + -acy (as in primacy) 1.: the quality or state of being supreme; also: supreme authority or power 2.: the position of being accepted or established as superior to all others in some field or activity < naval supremacy > < the supremacy among dramatists >