astronomical unit

noun

: a unit of length used in astronomy equal to the mean distance of the earth from the sun or about 93 million miles (150 million kilometers)

Example Sentences

Recent Examples on the Web

But Proxima Centauri is a star that's much smaller than the Sun, so its dust belt sits much closer, about 1 to 4 times the distance of the Earth to the Sun (called an astronomical unit or AU in space parlance). —John Wenz, Discover Magazine, 3 Nov. 2017

Bannister refers is an astronomical unit, which is the mean distance from the center of the earth to the center of the sun. —Tom Yulsman, Discover Magazine, 11 July 2016

The radio burst’s complex, magnetized environment is within about an astronomical unit (the distance between Earth and the sun) from its source, the researchers found. —Kristen Rogers, CNN, 23 Sep. 2022

The distance between Earth and the sun is one astronomical unit. —Ashley Strickland, CNN, 26 July 2021

To be sure, these planets — the two largest in our solar system — are far apart from each other, about 4.5 times the average distance between the Earth and the sun, what’s considered one astronomical unit. —Marisol Chávez, Dallas News, 21 Dec. 2020

In this system, the two inner stars, GW Ori A and B, orbit each other at a distance from Earth to the sun, called an AU or astronomical unit. —Ashley Strickland, CNN, 3 Sep. 2020

One astronomical unit is equal to the distance between the Earth and the sun. —Ashley Strickland, CNN, 16 Oct. 2019

The research team mapped the structure of a newborn star system called L1527, which has only 0.18 times the mass of the sun but whose surrounding envelope of gas stretches to more than 1,000 astronomical units (AU). —Sarah Lewin Frasier, Scientific American, 14 Feb. 2017

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Word History

First Known Use

1848, in the meaning defined above

Kids Definition

astronomical unit

noun

: a unit of length used in astronomy equal to the average distance of the earth from the sun or about 93 million miles (150 million kilometers)