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

• monarch
• sovereign
• emperor
• 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 latter track, a former Hot 100 ruler, makes its way back onto one Billboard tally this frame — 10 years after it was first released — as fans continue to stream the beloved cut. —Hugh McIntyre, Forbes.com, 7 Sep. 2025

Across centuries, rulers who built their power on fear or oppression seemed immovable in their day. —John Hope Bryant, Time, 6 Sep. 2025

Writers and rulers across Europe and the Americas have looked back to Virgil’s epic as a model for their own founding myths, in the construction of new nations, new colonies, new empires. —Literary Hub, 3 Sep. 2025

These include American Tanto, sheepfoot, serrated and saw blade options, as well as unconventional choices like a comb and can opener/ruler/wrench/seatbelt cutter single-piece multitool. —New Atlas, 2 Sep. 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