Rule (noun) — an official regulation or instruction that tells people what they must or must not do; a standard or principle; a period of governing power.
Rule (verb) — to govern a country or organisation; to give a formal legal decision; to draw a straight line using a ruler.
What Does Rule Mean?
Rule is one of the most versatile words in English, functioning as both a noun and a verb across a wide range of registers — from everyday conversation to legal proceedings and grammar textbooks. Its core meaning in both parts of speech centres on authority and order: a rule tells you what must happen, and to rule means to make that happen.
As a noun, rule covers official regulations ("school rules", "the rules of chess"), accepted principles ("a rule of grammar"), and periods or systems of government ("under colonial rule", "majority rule"). The fixed phrase as a general rule — as in the example sentence for this word — signals a habitual tendency rather than an absolute law. Similarly, rule of thumb refers to a rough practical guideline based on experience rather than an exact calculation.
As a verb, rule has three distinct uses: to exercise political or social control ("the dynasty ruled for three centuries"), to deliver an authoritative verdict ("the referee ruled the goal offside"), and to draw a straight line ("rule a line under the heading"). The phrasal verbs rule out (to eliminate as a possibility) and rule in (to include as a possibility) are especially important in professional and academic English.
Etymology
Rule descends from Old French reule and Latin regula, meaning a straight stick, a ruler, or a pattern of behaviour. The Latin root reg- also underlies regulate, regular, regiment, regal, and reign — all words connected with order, straightness, and authority. Rule entered Middle English around the 13th century, quickly developing both the physical sense (a tool for drawing straight lines) and the abstract sense (a principle to live by). The verb use appeared shortly after.
Example Sentences
| Sentence | Level & usage note |
|---|---|
| There is one simple rule: no running near the pool. | A2 — basic rule as a regulation |
| As a general rule, adverbs come before the adjectives they modify. | B1 — fixed phrase "as a general rule" for a habitual principle |
| The court ruled that the company had broken the contract. | B1 — verb: to give a formal legal decision |
| Doctors have ruled out a viral infection and are now testing for allergies. | B2 — phrasal verb "rule out" in a medical context |
| The principle of parliamentary sovereignty rules that no Act of Parliament can be overridden by any other domestic legal authority. | C1 — formal/legal register; verb expressing constitutional supremacy |
Collocations
| Collocation | Example |
|---|---|
| follow a rule | All players must follow the rules of the game. |
| break a rule | If you break the rules, you will be disqualified. |
| bend the rules | The manager agreed to bend the rules just this once. |
| set the rules | Parents should set clear rules for screen time. |
| as a general rule | As a general rule, longer sentences are harder to read. |
| rule of thumb | As a rule of thumb, allow 20 minutes per kilogram when roasting meat. |
| rule out | The police have not yet ruled out foul play. |
| ground rules | Let us establish some ground rules before the meeting begins. |
| majority rule | The new constitution was built on the principle of majority rule. |
| golden rule | The golden rule of customer service is to listen before you speak. |
Usage Notes
Key Patterns to Know
Rule + that-clause (verb): When rule means to give an official verdict, it is typically followed by a that-clause: "The judge ruled that the evidence was inadmissible." This pattern is especially common in legal, political, and journalistic English.
As a rule vs. as a general rule: Both phrases mean "usually" or "generally". As a general rule is slightly more emphatic and more common in formal and academic writing. As a rule is more common in everyday speech.
Rule of thumb: This idiom describes a practical guideline based on experience rather than precise measurement. It is neutral and common in both professional and informal contexts: "A rule of thumb is that you should save at least three months' salary."
Uncountable vs. countable: When referring to a period of government, rule is usually uncountable: "under military rule", "during British rule". When referring to individual regulations, it is countable: "a strict rule", "several rules".
Common Mistakes
Watch Out For
We must to follow the rules. (modal + base form — no "to" after "must")
We must follow the rules.
The judge ruled the defendant is innocent. ("that" is required after "rule" as a reporting verb)
The judge ruled that the defendant was innocent.
According to the rule, smoking is forbid here. ("forbid" needs the correct passive form)
According to the rules, smoking is forbidden here.
I ruled out to apply for the job. ("rule out" takes a gerund, not an infinitive)
I ruled out applying for the job.