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

An ancient Turkish name, Aslan was also used as a title for medieval Turkic rulers. —Lydia Wang, Parents, 12 Apr. 2026

Simply grab a ruler, pen, and blank sheet of paper to illustrate your space by substituting the dimensions of the room in feet for inches. —Cameron Beall, Southern Living, 11 Apr. 2026

Trump has asserted that Iran's new rulers are more moderate. —Kim Hjelmgaard, USA Today, 11 Apr. 2026

Besides being a record of events, the work is a crafty portrayal of kingship, presenting Akbar in an adulatory tone, as an exemplary and divinely favored ruler. —Encyclopedia Britannica, 9 Apr. 2026

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