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astronomical unit

noun, Astronomy.
a unit of length, equal to the mean distance of the earth from the sun: approximately 93 million miles (150 million km).
Abbreviation: AU.
Origin of astronomical unit
First recorded in 1900-05 Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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British Dictionary definitions for astronomical unit

astronomical unit

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 × 1011 metres or about 9.3 × 107 miles
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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astronomical unit in Science
astronomical unit
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. Compare light-year, parsec.

The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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astronomical unit in Culture

astronomical unit definition

The mean distance between the Earth and the sun, about 98 million miles or 150 million kilometers. It is often abbreviated as AU.

The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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