ruler: Meaning and Definition of

rul•er

1. a person who rules or governs; sovereign.
2. a strip of wood, metal, or other material having a straight edge and usually marked off in inches or centimeters, used for drawing lines, measuring, etc.
3. a person or thing that rules paper, wood, etc.
4. the planet primarily associated with any sign of the zodiac or any house of the horoscope: The ruler of Aries is Mars. The ruler of Taurus is Venus.