rule

rule — noun

1. An official or widely accepted instruction that sets out what is allowed and wha

1.nounA2
Definition

An official or widely accepted instruction that sets out what is allowed and what is forbidden in a given context, such as a game, school, or workplace.

Example

The school has a clear rule that students must wear uniforms every day.

rule + that-clause for stating what must be done

Before playing chess, Wei read all the rules of the game carefully.

collocation: rules of the game

Common collocations
  • strict rule
  • basic rule
  • follow the rules
  • break a rule
  • bend the rules
  • rules of the game
Synonyms
  • regulation

    more formal, often issued by an authority or government body

  • principle

    a broader, more general truth that guides behaviour, not a specific instruction

  • guideline

    a suggestion rather than a strict requirement

Antonyms
  • exception

    a case that does not follow the general rule

Usage Note

Countable noun. Often appears in the patterns 'rule that + clause' and 'rule about + noun/gerund'.

Common Mistakes

We must obey the low of the school.
We must obey the school rules.
'rule' is a specific instruction for a situation; 'law' is a formal system made by a government.

2. The span of time when a specific leader, government, or organisation holds autho

2.nounB1
Definition

The span of time when a specific leader, government, or organisation holds authority over a nation and decides its direction.

Example

The country enjoyed a long period of peace during the queen's rule.

collocation: during [someone's] rule

Many schools were built under the emperor's 40-year rule.

Common collocations
  • under the rule of
  • during the rule of
  • military rule
  • colonial rule
  • majority rule
  • home rule
Synonyms
  • reign

    specifically about the period a monarch rules

  • government

    focuses on the system or group in power, not the period

  • control

    more general; can apply to any kind of authority, not just over a country

Usage Note

Uncountable or countable. Often preceded by a possessive ('the king's rule') or an adjective + 'rule' ('military rule', 'colonial rule'). Frequently used with prepositions 'under', 'during', 'after'.

3. A long narrow object with a perfectly straight side and labelled units of length

3.nounB1
Definition

A long narrow object with a perfectly straight side and labelled units of length. You hold it against a surface to check how long something is or to make lines that are perfectly straight.

Example

Élise used a plastic rule to draw a straight line for her maths homework.

use a rule + to-infinitive

The carpenter checked the length of the wooden board with a metal rule.

Common collocations
  • plastic rule
  • metal rule
  • wooden rule
  • use a rule
  • measure with a rule
Synonyms
  • ruler

    the more common word in everyday English for this tool

  • tape measure

    a flexible tool for measuring curved or long surfaces

Usage Note

Also called a 'ruler'. More commonly 'ruler' in everyday speech; 'rule' sounds slightly more formal or technical.

Idioms

as a (general) rule

idiom

Usually, but not always, something happens or is true.

As a rule, Maya takes the train to work.

As a general rule, we avoid eating late at night.

bend/stretch the rules

idiom

To allow someone to ignore or change a rule for a special reason.

The teacher bent the rules and let Diego submit his homework late.

Can we stretch the rules and bring our dog inside?

the exception that proves the rule

idiom

A specific case that is different from the usual situation, but the general rule is still true.

Sara is always late, but today she arrived early—the exception that proves the rule.

Most birds fly, but penguins are the exception that proves the rule.

play by somebody’s (own) rules

idiom

To accept and follow the conditions set by another person in a situation.

If you want to join the club, you must play by their rules.

Brian refused to play by the manager's rules and left the company.

play by the rules

idiom

To behave fairly and honestly, following accepted standards.

Aiden always plays by the rules in business deals.

If everyone plays by the rules, the game will be fair.

the rule of law

idiom

A situation where all people and leaders must follow the laws of the country.

A strong democracy depends on the rule of law.

The rule of law protects citizens from unfair treatment.

a rule of thumb

idiom

A simple, practical method based on experience rather than exact measurement.

As a rule of thumb, water plants once a week.

A good rule of thumb is to save 10% of your income.

the rules of the game

idiom

The accepted standards or guidelines that people follow in a particular situation.

In politics, you must learn the rules of the game.

New employees need to understand the rules of the game at work.

work to rule

idiom

To protest by following every rule exactly, which slows down work.

The bus drivers decided to work to rule to demand better pay.

When the staff worked to rule, the office became very slow.

rule — verb

Word family

  • ruler
    nounA2
  • ruled
    adjectiveB2
  • ruler
    noun (person)B1
  • ruling
    nounB1
  • overrule
    verbC1
  • unruly
    adjectiveC1

Synonym discussion

Sense: noun/1

All four words refer to standards that direct behaviour, but they differ in formality and flexibility. A 'rule' is the broadest term — it can apply to board games, schools, clubs, or workplaces. A 'regulation' is more formal and official, typically issued by a government or regulatory body; think of safety regulations in a factory or traffic regulations. A 'law' is the most formal — it is a rule passed by a government and enforced by courts, with legal penalties for breaking it. A 'guideline' is the least strict; it offers advice or recommended practice rather than a requirement. For example: 'The school has a rule against running in the hallways' (local, enforceable by teachers). 'The government introduced new regulations on food labelling' (official, legally binding). 'It is against the law to drive without insurance' (legal, serious consequences). 'The doctor gave me some guidelines for a healthy diet' (suggestions, not binding).

rule ↗regulation ↗law ↗guideline ↗

Common collocations

Nouns

  • rule changes
  • rule book
  • rule breakers
  • rule of law

Adverbs

Phrases

Prepositions

Etymology

LatinFrenchEnglish

The word 'rule' came into English through Old French 'riule', which came from Latin 'regula', meaning a straight stick or a pattern to measure against. The Latin word 'regula' itself comes from the verb 'regere', meaning 'to lead straight' or 'to guide'. This explains why 'rule' has two very different-looking meanings: the sense of a measuring tool (a straight edge) and the sense of an accepted principle (something you measure your behaviour against). The political meaning — having power over a country — grew out of the idea of 'guiding' or 'directing' people.