Source : Webster's Revised Unabridged Dictionary (1913)

Cathay \Ca*thay"\, n.
   China; -- an old name for the Celestial Empire, said have
   been introduced by Marco Polo and to be a corruption of the
   Tartar name for North China (Khitai, the country of the
   Khitans.)

         Better fifty years of Europe than a cycle of Cathay.
                                                  --Tennyson.

Source : WordNet®

Cathay
     n : an archaic or literary name for China