The Collaborative International Dictionary of English v.0.48:

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.)
   [1913 Webster]

         Better fifty years of Europe than a cycle of Cathay.
                                                  --Tennyson.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Cathay
    n 1: a communist nation that covers a vast territory in eastern
         Asia; the most populous country in the world [syn: China,
         People's Republic of China, mainland China, Communist
         China, Red China, PRC, Cathay]

U.S. Gazetteer Places (2000):

Cathay, ND -- U.S. city in North Dakota
   Population (2000):    56
   Housing Units (2000): 37
   Land area (2000):     0.183090 sq. miles (0.474200 sq. km)
   Water area (2000):    0.003658 sq. miles (0.009474 sq. km)
   Total area (2000):    0.186748 sq. miles (0.483674 sq. km)
   FIPS code:            12820
   Located within:       North Dakota (ND), FIPS 38
   Location:             47.553931 N, 99.411403 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Cathay, ND
    Cathay