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 confrontation was set off in July of 1956, when Egypt’s ruler, Colonel Gamal Abdel Nasser, a charismatic populist, nationalized the Anglo-French company that had operated the canal since its creation in 1869, during the colonial era. —Ishaan Tharoor, New Yorker, 30 Mar. 2026

Since the fall of Assad in December 2024, members of the country’s Alawite, Druze and Christian minorities have been subjected to attacks by gunmen loyal to the country’s new Islamist rulers. —ABC News, 28 Mar. 2026

Erasing historic figures from the public sphere is an exercise in power going back to the pharaohs, a way rulers ensured future generations couldn’t learn about their enemies. —Gustavo Arellano, Mercury News, 27 Mar. 2026

An additional set including the ruler and eternal pen will cost an extra $49 for backers and $89 at retail. —Maryna Holovnova, New Atlas, 26 Mar. 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