autocracy

From auto- + -cracy, tracing to Ancient Greek αὐτοκρατία (autokratía), meaning a system of government by one person with absolute power. That word combines αὐτός (autós, "self, alone") with κράτος (krátos, "power") and the feminine abstract-noun suffix -ία.

The word has kept its core sense intact from Greek onward: rule by a single self-holding power, rather than a shared or distributed one.

It's closely tied to Ancient Greek αὐτοκρατής (autokratḗs), "one who governs alone" — the personal counterpart to this abstract noun of rule.