Meaning of astronomical unit

as'tronom'ical u'nit

Pronunciation: [key]
— Astron. Astron.
  1. a unit of length, equal to the mean distance of the earth from the sun: approximately 93 million miles (150 million km). Abbr.: AU
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
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