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

The vote underscores the staying power of Africa’s aging leaders on a continent that has some of the world’s oldest rulers despite boasting the youngest population globally. — Farai Mutsaka, Los Angeles Times, 18 June 2026

Swift passes both Rihanna and Drake, who sit side-by-side with 14 rulers apiece. — Hugh McIntyre, Forbes.com, 18 June 2026

This season’s third episode should be recognized as the best hour of the series so far, a thorough, process-centric portrait of what’s required to lead the commonfolk and sit on the maybe-sentient Iron Throne, which is famed for its ability to accept or reject a ruler. — Roxana Hadadi, Vulture, 18 June 2026

Throughout history, rulers and political movements have used public spectacles of combat to evoke courage, sacrifice, collective strength and national purpose. — Scott Atran, The Conversation, 17 June 2026

Word History

First Known Use

14th century, in the meaning defined at sense 1

Phrases Containing ruler

• co-ruler

Rhymes for ruler

• cooler
• 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