# approximation

/əˌpɹɑksəˈmeɪʃən/ (US) · /ɐpɹˌɒksɪmˈeɪʃən/ (UK)

Source: https://englishreference.com/word/approximation
Updated: 2026-08-27

## Senses

### 1. an estimate

noun · CEFR B2

a value or amount that is nearly correct but not exact.

For teachers: a value or quantity that is nearly but not exactly correct, often used when precise measurement is impossible or unnecessary.

- The figure of ten thousand dollars is just a rough approximation of the total cost.
- For the purposes of the initial budget proposal, a rough approximation of the overhead costs will suffice until the audit is complete.

Usage: Often used with the adjectives 'rough', 'close', or 'near'.

### 2. a similar version

noun · CEFR C1 · Academic

something that is similar to another thing but not exactly the same.

For teachers: a thing that is similar to something else, typically a less perfect or less complete version.

- His latest painting is a close approximation of the style used by the old masters.
- The simulated environment provides a functional approximation of deep-sea conditions, allowing researchers to test equipment without the risks of actual deployment.

Usage: Frequently followed by the preposition 'of'.

### 3. the process of estimating

noun · CEFR C1 · Technical

the act of coming close to a result or value.

For teachers: the process of approaching a value, state, or condition through successive stages of increased accuracy.

- The scientist used a method of approximation to find the answer to the complex problem.
- The algorithm relies on successive approximation to reach a stable solution within the specified margin of error.

## Examples

- The map shows an approximation of the distance.
- The budget is only an approximation since we do not know the final costs.
- In theoretical physics, the model serves as a useful approximation, though it simplifies complex quantum interactions for the sake of clarity.

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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.