The Collaborative International Dictionary of English v.0.48:

Karroo \Kar*roo"\ (k[.a]r*r[=oo]"), n.; pl. Karroos
   (k[.a]r*r[=oo]z").
   One of the dry table-lands of South Africa, which often rise
   terracelike to considerable elevations. [Also karoo.]
   [1913 Webster]

   The Great Karroo, or The Karroo, a vast plateau, in Cape
      Colony, stretching through five degrees of longitude, at
      an elevation of about 3,000 feet.
      [1913 Webster]