# ruler

/ˈɹuɫɝ/ (US) · /ɹˈuːlɐ/ (UK)

Source: https://englishreference.com/word/ruler
Updated: 2026-06-20

## Senses

### 1. measuring tool

noun · CEFR A1

a flat, straight tool used for measuring length or drawing straight lines.

For teachers: a rigid, flat instrument with marked graduations used for measuring linear distance or as a straightedge.

- Use a ruler to make sure the line is exactly ten centimetres long.
- The student used a wooden ruler to measure the dimensions of the specimen before sketching it in her notebook.

### 2. leader

noun · CEFR A2

a person who has the power to control a country or group, like a king or queen.

For teachers: a person who exercises supreme authority or dominion over a territory or people.

- The ancient ruler built many beautiful temples during his long reign.
- Historians often debate whether the ruler was a benevolent visionary or a tyrant who prioritised expansion over the welfare of his subjects.

### 3. to hit with a ruler

verb · CEFR C2 · Archaic

to hit someone with a ruler as a punishment.

For teachers: to strike a person, typically a student, with a ruler as a form of corporal punishment.

- In the old days, teachers might ruler a student for being late.
- The memoir describes a harsh Victorian classroom where the master would ruler any child who failed to recite their verses perfectly.

Usage: This verb is transitive and takes a direct object, usually a person.

Teaching tip: This sense is archaic and refers to historical school discipline; it is not used in modern educational contexts.

## Examples

- Use a ruler to draw a straight line.
- The student pulled a plastic ruler from her pencil case to measure the width of the textbook.
- Architects often prefer steel rulers for their durability and precision when drafting manual sketches on heavy paper.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.