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

Two lasers replace hardware Optical frequency combs work much like rulers for light. — Neetika Walter, Interesting Engineering, 17 Oct. 2026

To varying degrees, respondents in these countries—Egypt, Iran, Iraq, Saudia Arabia, and Turkey—expressed an increasing preference for liberal values, even as their rulers sought to suppress popular demands for democratic change. — Mansoor Moaddel, Foreign Affairs, 15 Oct. 2026

The second find consists of part of a statue of a royal personage along with its head, which was adorned with the striped cloth associated with ancient Egyptian rulers. — Anne Doran, ARTnews.com, 14 Oct. 2026

While many Hindus worship Rama, Sita and Hanuman as deities, Hindu nationalists have also presented Rama as a historical figure – the legendary ruler of the ancient kingdom of Ayodhya. — Sohini Sarah Pillai, The Conversation, 14 Oct. 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