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 of ruler

• monarch
• emperor
• sovereign
• 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

These Benin Bronzes chronicled rulers, court life, and spiritual practices, offering a rare insight into the sophistication of the kingdom. —Amir Daftari, MSNBC Newsweek, 7 Dec. 2025

Then, as Mars (ruler of your relationship sector) and the sun slip into Capricorn, there is greater focus on your personal life, particularly your sense of stability and the desire to build towards a relationship that feels like your very own sanctuary. —Valerie Mesa, PEOPLE, 5 Dec. 2025

Venus, your planetary ruler, has moved into Sagittarius and is lighting up your communication sector. —Dossé-Via Trenou, Refinery29, 30 Nov. 2025

Ultimately, the International Criminal Court charged Sudan's former dictatorial ruler Omar al-Bashir with genocide. —Patrick Reevell, ABC News, 28 Nov. 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