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

• autocrat
• monarch
• potentate
• sovereign
• sovran

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 arid peninsula off Saudi Arabia in the Persian Gulf, similar in size to Connecticut, boasts deep reserves of oil and gas that have made the country the fourth-wealthiest in the world by per capita GDP and enriched its rulers, the House of Thani. —Jeremy Bogaisky, Forbes.com, 14 May 2025

Flashpoint Kashmir has been a flashpoint since 1947, when British India was hastily divided into two by its former colonial rulers. —Rhea Mogul, CNN Money, 14 May 2025

Saudi Arabia is the first stop on a four-day trip to the Middle East for Mr. Trump, and he was greeted on the tarmac at the airport in Riyadh by the kingdom's de facto ruler, Crown Prince Mohammed bin Salman. —Kaia Hubbard, CBS News, 13 May 2025

Trump is expected to attend a dinner with Saudi Arabia's de facto ruler, Crown Prince Mohammed bin Salman, later on Tuesday. —Callum Sutherland, Time, 13 May 2025

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