Potentate (from the Latin potens, 'powerful') is an informal term for a person with potent, usually supreme, power.
Potentate is the title used by the A.A.O.N.M.S. (Shriners) for the head of a local Shrine. The head of the Shriners of North America is titled the Imperial Potentate. The staff and volunteers of the ISA (International Instrumentation Symposium) are also called potentates.
The term was used by the Christian Church to describe Jesus, it can be found in 1 Timothy 6:15. One example of this use is in the hymn "Crown him with many crowns" in which Jesus is described as "potentate of time"
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.
The term is also used to describe an ambassador performing negotiations on behalf of a large group. (States are often styled powers, in diplomatic language, even if politically and militarily weak).