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

See Examples For:

approximation

Their books have both a stance on the world and a willingness to recognize the human beings, the political situations, the complicated relationships that make any stance, at best, an approximation.

From The Wall Street Journal ● Jul. 19, 2026

A behind-the-scenes teaser trailer boasts of expending 25 tons of propane to create a realistic approximation of dragon fire and setting a new world record for setting stunt performers on fire in a single take.

From Salon ● Jun. 24, 2026

While it’s unclear exactly how many people SpaceX employs across the U.S., that approximation from Shotwell implies that about a third of the company’s staff is based in Hawthorne.

From MarketWatch ● May 19, 2026

When the supply side is stable, that approximation works well enough.

From Barron's ● Apr. 30, 2026

For a long time, this was sufficient justification for Friedmann’s assumption—as a rough approximation to the real universe.

From "A Brief History of Time: And Other Essays" by Stephen Hawking