King or president
(Other definitions for ruler that I've seen before include "One governing" , "Maharaja, e.g." , "overlord" , "One who holds sway and effects government" , "liner?" .)
I believe this is a double definition.
'king' is the first definition.
(I know that Arthur has the occupation king)
'president' is the second definition.
(I know that Arthur is a president)
'or' is the link.
(Other definitions for arthur that I've seen before include "Dudley Moore film" , "Sir --- Conan Doyle" , "Husband of Guinevere" , "Owner of Excalibur" , "Greed" .)