\South"down`\, a.
Of or pertaining to the South Downs, a range of pasture hills
south of the Thames, in England.
{Southdown sheep} (Zo["o]l.), a celebrated breed of
   shortwooled, hornless sheep, highly valued on account of
   the delicacy of their flesh. So called from the South
   Downs where the breed originated.

\South"down`\, n.
A Southdown sheep.