Monarchy
Part of speech: noun
Definition: A government with a hereditary head of state (whether as a figurehead or as a powerful ruler).
Dynasty
Part of speech: noun
Definition: A series of rulers or dynasts from one family.
Example sentence: Many and subtle are the ideological weapons that the State has wielded through the centuries. Once excellent weapon has been tradition. The longer that the rule of a State has been able to preserve itself, the more powerful this weapon; for then, the X Dynasty or the Y State has the seeming weight of centuries of tradition behind it.