ruler

ruler — noun

1. A person who holds the highest authority in a country or region and makes decisi

1.nounB1
Definition

A person who holds the highest authority in a country or region and makes decisions that affect the people living there.

Example

Sayaka said a wise ruler must think about the needs of all citizens.

adjective + ruler + must + verb — describing ideal qualities

The emperor was a strict ruler who demanded loyalty from every official.

Common collocations
  • wise ruler
  • strict ruler
  • elected ruler
  • ancient ruler
  • depose a ruler
  • under a ruler
Synonyms
  • leader

    more general term for anyone who guides or directs others; 'ruler' implies formal authority over a country or region

  • monarch

    a hereditary ruler such as a king or queen, ruling for life or until abdication

  • sovereign

    a supreme ruler, especially in a monarchy; emphasises total independence and authority

  • governor

    the head of a region within a larger political system, such as a state or province, rather than a whole country

Antonyms
  • subject

    a person who lives under the authority of a ruler

  • citizen

    a member of a country with rights, rather than someone who governs it

Grammar Patterns

ruler + of + country/region

adjective + ruler

Usage Note

Often paired with an adjective that describes the nature of the rule, such as 'fair ruler', 'harsh ruler', or 'elected ruler'. The word can refer to monarchs, presidents, or any person with supreme governing power.

Common Mistakes

The queen was a strict ruler of her household.
The queen was a strict ruler of the kingdom.
'ruler' in this sense means a leader of a country or large region, not of a private home.

2. A measuring tool that is a flat strip with printed marks for units of length, us

2.nounA2
Definition

A measuring tool that is a flat strip with printed marks for units of length, used for checking the size of things and guiding a pencil to produce even lines.

Example

Reuben took a plastic ruler from his bag to measure the length of the book.

take + a ruler + to measure — classroom collocation

The teacher asked everyone to use a ruler when drawing the diagram.

Common collocations
  • plastic ruler
  • metal ruler
  • wooden ruler
  • 30 cm ruler
  • use a ruler
  • measure with a ruler
  • draw with a ruler
Synonyms
  • measuring stick

    a more general term that includes rulers, yardsticks, and tape measures

  • straightedge

    a ruler without measurement markings, used only for drawing straight lines

Grammar Patterns

ruler + for + purpose

use + a ruler + to-infinitive

adjective + ruler

Usage Note

Described by material (plastic ruler, wooden ruler) or length (a 15 cm ruler, a 12-inch ruler). In technical drawing, a ruler without markings is called a straightedge.

Word family

Synonym discussion

Sense: noun/1

All four words describe someone who holds power over others, but they differ in scope and connotation. 'Ruler' is the broadest term, covering any person who governs a country or region, whether a king, president, or emperor. 'Leader' is even more general and can apply to anyone who guides a group, not necessarily with formal political power. 'Monarch' specifically refers to a hereditary ruler such as a king or queen — the position is passed down through a family line. 'Sovereign' emphasises supreme and independent authority, often used in legal or formal contexts to describe a ruler who answers to no higher power. 'Dictator' carries a strongly negative connotation of a ruler who holds absolute power, often through force, and limits the freedoms of the people. For example, one might say 'The queen was a beloved monarch,' but 'The general became a brutal dictator.'

leader ↗monarchsovereign ↗dictator ↗

Common collocations

Prepositions

Etymology

LatinOld FrenchMiddle EnglishEnglish

Ruler comes from Middle English 'reuler', formed from the verb 'rule' (meaning to govern or control) plus the agent suffix '-er' (a person who does something). The verb 'rule' traces back through Old French 'riuler' to Latin 'regula', meaning a straight stick or guiding principle. The measuring-tool sense developed from the same Latin root: a ruler was originally a straightedge used for 'ruling' (drawing straight lines), and the political sense of a person who governs grew alongside it.