Enkrateia
In Ancient Greek philosophy, enkrateia (Greek ἐνκράτεια, "in power - from ἐν (en, “in”) + κράτος (krátos, “power”) is a state of power over something, usually a state of self-control and self-mastery where one holds power over one's own passions and instincts. It was first used in the context of self-control by three of Socrates' students: Isocrates, Xenophon and Plato.