| Term: | Astronomical unit |
| Definition: |
A unit of length equal to 149,597,870,700 m exactly, with symbol 'au' (re-definition at the International Astronomical Union's 28th General Assembly in Beijing, China, August 20-31). The astronomical unit equals 1.5813 x 10^-5 light-years and 4.8481 x 10^-6 parsecs. |