astronomical unit

American  

noun

Astronomy.

1. a unit of length, equal to the mean distance of the earth from the sun: approximately 93 million miles (150 million km). AU

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astronomical unit British  

noun

1. a unit of distance used in astronomy equal to the mean distance between the earth and the sun. 1 astronomical unit is equivalent to 1.495 × 10 ¹¹ metres or about 9.3 × 10 ⁷ miles

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astronomical unit Scientific  

/ ăs′trə-nŏm′ĭ-kəl /

1. A unit of length equal to the average distance from Earth to the Sun, approximately 149.6 million km (92.8 million mi). It is used especially to measure distances within the solar system.

2. Compare light-year parsec

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astronomical unit Cultural  

1. The mean distance between the Earth and the sun, about 93 million miles or 150 million kilometers. It is often abbreviated as AU.

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Etymology

Origin of astronomical unit

First recorded in 1900–05

Compare meaning

How does astronomical-unit compare to similar and commonly confused words? Explore the most common comparisons:

• astronomical unit vs. light-year

Example Sentences

The research also sheds light on another puzzle: why Earth, Venus and Mars orbit near 1 astronomical unit from the sun instead of spiraling inward, a common outcome in many planetary systems observed around other stars.

From Science Daily

The average distance between Earth and the sun, what astronomers call an astronomical unit, is defined as 149,597,870.7 km.

From Scientific American

An astronomical unit, which measures the distance between the Earth and the sun, is approximately 93 million miles.

From Fox News

One AU, or astronomical unit, is approximately 93 million miles, or the distance between the Earth and the sun.

From Fox News

One astronomical unit is the equivalent of 93 million miles or the distance between the Earth and the sun.

From Fox News