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 single became his eleventh career ruler earlier this year. — Hugh McIntyre, Forbes.com, 30 June 2026

But the new ruler of the Iron Throne has to make a power statement. — Bryan Alexander, USA Today, 29 June 2026

The practice, many legal historians believe, dates to the 1600s and 1700s, with European rulers encouraging migration to the expanding American colonies. — Julie Watson, Los Angeles Times, 29 June 2026

Jones said Shiite rulers in several South Asian kingdoms sponsored processions and other commemorations of Hussein’s martyrdom, helping turn them into public events that drew wider audiences. — ABC News, 25 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