ruler

noun

rul·​er ˈrü-lər 

1

: one that rules

specifically : sovereign

2

: a worker or a machine that rules paper

3

: a smooth-edged strip (as of wood or metal) that is usually marked off in units (such as inches) and is used as a straightedge or for measuring

rulership

ˈrü-lər-ˌship 

noun

Synonyms

• monarch
• sovereign
• emperor
• king

Examples of ruler in a Sentence

a summit attended by a number of rulers from around the world

This ruler shows inches and centimeters.

Recent Examples on the Web

But the people in most democracies and the rulers in most non-democracies have other goals. —Bill Conerly, Forbes.com, 21 Aug. 2025

By telling stories, our species became the unrivaled ruler of the earth, with devastating consequences. —Madeleine Beekman august 11, Literary Hub, 11 Aug. 2025

Amouage was founded in 1983 by the previous ruler of Oman, Sultan Qaboos bin Said Al Said, based on his vision to create a perfume as a gift that represented Oman. —Ritu Upadhyay, Footwear News, 1 Aug. 2025

Mars, your planetary ruler, enters Libra on August 6th, entering your sector of closure and spiritual endings for the next six weeks. —Dossé-Via Trenou, Refinery29, 30 July 2025

Word History

First Known Use

14th century, in the meaning defined at sense 1

Phrases Containing ruler

• co-ruler

Rhymes for ruler

• cooler
• jeweller
• schooler
• schuller
• preschooler
• vestibular

Kids Definition

ruler

noun

rul·​er ˈrü-lər 

1

: sovereign entry 1 sense 1

2

: a straight strip of material (as wood or metal) marked off in units and used as a guide in drawing lines or for measuring