01 n. the unit of length equal to the mean distance of the Earth from the sun, about 93 million miles (150 million kiometers); -- used almost exc…
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1.
the unit of length equal to the mean distance of the Earth from the sun, about 93 million miles (150 million kiometers); -- used almost exclusively in astronomy, or to describe astronomical distances.(Astron.)
Syn.
astronomical unit, AU, A.U.