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:
After America defeated the Marianas’ colonial ruler in the Spanish-American War, it wanted a base to project power over the western Pacific.
From Salon ● Oct. 13, 2026
Piqued, Burkina's military ruler Ibrahim Traore complained the country's football was "in a sorry state" and threatened "significant decisions" to "remedy it".
From Barron's ● Oct. 8, 2026
This effectively alters the cosmic ruler used to measure distances and, in turn, the value of the Hubble constant inferred from the model, helping to ease the Hubble tension.
From Science Daily ● Oct. 4, 2026
She was briefly proclaimed England’s ruler in 1553, following the death of her cousin Edward VI, who had named Jane as his heir.
From The Wall Street Journal ● Sep. 25, 2026
I rush over to my backpack and take out the thin metal ruler we use in geometry.
From "Fast Pitch" by Nic Stone
"I would give them notepads, pens, calculators and a stationery set, for example pencil cases, rulers and protractors."
From BBC ● Nov. 2, 2026
These were people who ruled a country, the heirs to generations of rulers.
From Slate ● Oct. 19, 2026
"I appeal to our rulers," he said, adding that Hammad had been "doing well in school" before the tragedy.
From Barron's ● Oct. 16, 2026
Ms. Horn hopes, she writes, to convey that Judaism “is a movement built on laws that don’t rely on human rulers, built on an idea of commandedness that taught the world that freedom requires responsibility.”
From The Wall Street Journal ● Aug. 31, 2026
Hellenistic rulers, it is said, trivialized Greek civic life by reducing it to pompous pageantry and contests over who could best flatter the king.
From "Circumference" by Nicholas Nicastro
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Get a wordDefinitions 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.
