# known

/ˈnoʊn/ (US) · /nˈəʊn/ (UK)

Source: https://englishreference.com/word/known
Updated: 2026-06-19

## Senses

### 2. familiar or recognized

adjective · CEFR A2

familiar to people or easy to recognize.

For teachers: familiar, recognized, or established through experience or observation.

- It is a known fact that smoking is bad for your health.
- The patient had no known allergies to the medication, so the doctor proceeded with the standard prescription.

### 3. famous for something

adjective · CEFR B1

famous or well-regarded for a specific reason.

For teachers: widely recognized or famous, often followed by 'as' or 'for'.

- The city is known for its beautiful parks and old buildings.
- The author is primarily known for her historical novels, though she has recently experimented with science fiction.

### 4. a fixed value

noun · CEFR C1 · Technical

something that is already certain or a value that is already calculated.

For teachers: a fact or variable whose value or nature is already determined or established.

- In this equation, the speed of the car is a known.
- When solving for the trajectory, we must first isolate the knowns from the variables to simplify the calculation.

## Examples

- I have known my best friend since we were children.
- The scientist is widely known for her groundbreaking research on renewable energy sources.
- Although the risks were well known to the board of directors, they proceeded with the merger to secure a larger market share.

---

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.