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

Krishnadevaraya, its most celebrated ruler, was part of the Tuluva dynasty (the third dynasty of the Vijayanagara empire). — Andrew Pereira, Encyclopedia Britannica, 3 Aug. 2026

Oft referred to as the king and queen of Italian wine, Barolo and Barbaresco can truly reign together as co-rulers, especially when produced by those with a foot in each appellation. — Mike Desimone, Robb Report, 2 Aug. 2026

Hürrem takes inspiration from the 16th‑century romance between Ottoman ruler Sultan Süleyman the Magnificent and his chief consort Roxelana, who became Hürrem Sultan upon winning his heart. — Lilian Raji, Forbes.com, 1 Aug. 2026

For most of history, order was imposed from above because rulers did not trust ordinary people with power. — Keith Krach, Fortune, 1 Aug. 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