ruler
Americannoun
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rulers
plural
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a person who rules or governs; sovereign.
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Also 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.
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a person or thing that rules paper, wood, etc.
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Astrology. 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.
noun
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a person who rules or commands
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Also called: rule. a strip of wood, metal, or other material, having straight edges graduated usually in millimetres or inches, used for measuring and drawing straight lines
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Etymology
Origin of ruler
Middle English word dating back to 1325–75; see origin at rule, -er 1
Explanation
The leader of a country is a ruler. If you're a queen, a sultan, or a czar, you're a ruler. Besides "person who rules or governs," you can define ruler as a measuring device that's marked with inches or centimeters. You can measure the diameter of a circle with a ruler, and you can also draw a perfectly straight line using its edge. Both meanings stem from the verb rule, "to exercise power" or "to control," which came to also mean "mark with lines" in the 1590s.
Vocabulary lists containing ruler
Measurement and Data, List 2
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"Culture Clash"
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Measurement and Data
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
The city had no known palaces where a ruler or ruling class could have controlled these tools of commerce and administration.
From Science Daily ● Jul. 30, 2026
For the entirety of “Avatar,” Aang’s loved ones and allies try to persuade him that the only way to stop the Fire Nation is to kill its despotic ruler, Lord Ozai.
From Salon ● Jul. 8, 2026
President Ahmed al-Sharaa has been rebooting Syria's international credentials and seeking to revive his struggling country after toppling longtime ruler Bashar al-Assad in December 2024.
From Barron's ● Jul. 6, 2026
It offers not only a fresh portrait of India's most controversial Mughal ruler, but also a rare glimpse of how one of the world's great early-modern empires actually worked.
From BBC ● Jun. 27, 2026
Then Mr. Kennel showed up with his ruler.
From "Worth" by A. LaFaye
There is no sign that Kuwait’s rulers are planning a fundamental shift away from heavy reliance on the U.S. as their main security partner.
From The Wall Street Journal ● Jul. 31, 2026
Its carefully planned streets and advanced brick drainage systems indicate that resources were directed toward shared infrastructure rather than monuments celebrating rulers or religious elites.
From Science Daily ● Jul. 30, 2026
They pieced together the story of the people she may have painted in Chennai in India, known then as Madras, including the Nawabs of Arcot, the local Mughal rulers.
From BBC ● Jul. 23, 2026
Vang Vieng has been a fixture on the Southeast Asia backpacker trail since Laos' secretive communist rulers opened the country to tourism decades ago.
From Barron's ● Jul. 17, 2026
I taught them how to use rulers, compasses, protractors, and triangular scales.
From "Reaching for the Moon" by Katherine Johnson
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
