Page "Potentate" Paragraph 2

Originally, it designated the absolute monarch ( synonymous with autocrat, which was also used as a title ) of a great state.

From the negative connotations of such rule, mainly in the Orient, derives its generalized use for the head of any totalitarian and / or abusive regime, as a synonym for despot, dictator, or tyrant ( all three in the modern, derogatory sense, contrary to a rather lofty historical origin ), also at a sub-state level, or even a big boss in private life.