n. 25B6; noun
her mastery of the language : PROFICIENCY, ability, capability; knowledge, understanding, comprehension, familiarity, command, grasp, grip.
they played with tactical mastery : SKILL, skilfulness, expertise, dexterity, finesse, adroitness, virtuosity, prowess, deftness, proficiency; informal know-how.
man's mastery over nature : CONTROL, domination, command, ascendancy, supremacy, pre-eminence, superiority; triumph, victory, the upper hand, the whip hand, rule, government, power, sway, authority, jurisdiction, dominion, sovereignty.