Au - Definition
au
n 1: a soft yellow malleable ductile (trivalent and univalent)
metallic element; occurs mainly as nuggets in rocks and
alluvial deposits; does not react with most chemicals but
is attacked by chlorine and aqua regia [syn: gold, Au,
atomic number 79]
2: a unit of length used for distances within the solar system;
equal to the mean distance between the Earth and the Sun
(approximately 93 million miles or 150 million kilometers)
[syn: Astronomical Unit, AU]