tyr·an·ny 
(tĭrə-nē)
(tĭrə-nē)n. pl. tyr·an·nies
1. Unjust or oppressive governmental power: "He tended to see the Crown as the benign center of the empire and Parliament as the malevolent source of tyranny" (Gordon S. Wood).
2. A government in which a single ruler is vested with absolute power: people liberated from a brutal tyranny.
3. The office, authority, or jurisdiction of an absolute ruler: Pisistratus held the tyranny of Athens.
4.
a. The oppressive or unjust use of power: parental tyranny.
b. A tyrannical act: refused to submit to her husband's tyrannies.
5. An oppressive or harshly limiting condition: the tyranny of social expectations.
[Middle English tyrannie, from Old French, from Late Latin tyrannia, from Greek turanniā, from turannos, tyrant.]