ruler
noun
[ ˈruːlə ]
• a person exercising government or dominion.
Similar:
leader,
sovereign,
monarch,
potentate,
crowned head,
head of state,
overlord,
chief,
chieftain,
lord,
dynast,
despot,
dictator,
tyrant,
autocrat,
tetrarch,
ethnarch,
autarch,
• a straight strip or cylinder of plastic, wood, metal, or other rigid material, typically marked at regular intervals and used to draw straight lines or measure distances.