Despotism
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
That abuse of government where the sovereign power is not divided, but united in the hands of a single man, whatever may be his official title. It'is not, properly, a form of government.
Toullier, Dr. Civ. Fr. tit. pr6l. n.
32. "Despotism" is not exactly synonymous with "autocracy," for the former involves the idea of tyranny or abuse of power, which is not necessarily implied by the latter. Every despotism is autocratic; but an autocracy is not necessarily despotic.