Pronunciation: (rOO'lur), [key]
1. a person who rules or governs; sovereign.
2. Also,rule.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. Astrol.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.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.