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

No ruler-wielding schoolmarm can impart the urgency of learning the way hunger can. —John Phillips, Outdoor Life, 14 May 2026

The storyline will follow Shaikh Ali from his time as a young ruler who inherits Bahrain’s throne at 19-years-old following the death of his father. —Melanie Goodfellow, Deadline, 13 May 2026

Iran has installed rulers even more conservative and hardline than their predecessors. —Mercury News & East Bay Times Editorial Boards, Mercury News, 7 May 2026

In the show Prince Adam is the son of Eternia’s rulers, King Randor and Queen Marlena. —Sanat Pai Raikarall, Encyclopedia Britannica, 4 May 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