- au
- au a.u. n.
1. (Astron.) 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.
Syn: astronomical unit, AU, A.U. [WordNet 1.5]
The Collaborative International Dictionary of English. 2000.
