A sole or supreme ruler; a sovereign; the highest ruler; an emperor, king, queen, prince, or chief.
- One who reigns over a state or territory, usually for life and by hereditary right, especially:
- A sole and absolute ruler.
- A sovereign, such as a king or empress, often with constitutionally limited authority: a constitutional monarch.
- One that commands or rules: "I am monarch of all I survey” ( William Cowper).
- One that surpasses others in power or preeminence: "Mont Blanc is the monarch of the mountains” ( Byron).
- A monarch butterfly.