approximation

American  

[uh-prok-suh-mey-shuhn] / əˌprɒk səˈmeɪ ʃən /

noun

1. a guess or estimate.

   Ninety-three million miles is an approximation of the distance of the earth from the sun.

2. nearness in space, position, degree, or relation; proximity; closeness.

3. Mathematics, Physics. a result that is not necessarily exact, but is within the limits of accuracy required for a given purpose.

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approximation British  

/ əˌprɒksɪˈmeɪʃən /

noun

1. the process or result of making a rough calculation, estimate, or guess

   he based his conclusion on his own approximation of the fuel consumption

2. an imprecise or unreliable record or version

   an approximation of what really happened

3. maths an inexact number, relationship, or theory that is sufficiently accurate for a specific purpose

4. maths

   1. an estimate of the value of some quantity to a desired degree of accuracy

   2. an expression in simpler terms than a given expression which approximates to it

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Other Word Forms

• approximative adjective

Etymology

Origin of approximation

1400–50; late Middle English approximacioun (< Middle French ) < Medieval Latin approximātiōn-, stem of approximātiō. See approximate, -ion

Explanation

An approximation is a rough estimate or guess at something. When you write a budget for the month, you're making an approximation of how much you're going to spend. You can't be certain of the exact amount. Like approximately or proximity, approximation comes from the Latin proximus which means "nearest." An approximation is the nearest estimate you can get without having the precise size or measure of something. It's a ballpark figure. When you set out for work in the morning, the amount of time you give yourself to get there is an approximation. Depending on traffic and weather, you can never know exactly how long the trip will take.

Example Sentences

While the data does not specifically detail children per filer, it does show tax exemptions claimed, which is a pretty good approximation.

From MarketWatch • Feb. 16, 2026

Using a publicly traded stock as a proxy for a privately held company provides only a rough approximation of the private firm’s worth.

From Barron's • Feb. 3, 2026

The final result is utterly unique to Blumberg and Fastvold, a period character study by way of trance and an experiential approximation of religious fervor.

From Los Angeles Times • Dec. 24, 2025

Despite this complexity, a close approximation of its motion can be captured with a simple linear equation that uses only the launch speed and angle.

From Science Daily • Dec. 22, 2025

Then she pulled an energy bar and her canteen out of her backpack for some approximation of lunch.

From "Breadcrumbs" by Anne Ursu