The Collaborative International Dictionary of English v.0.48:

mainland China \mainland China\ n.
   The People's Republic of China, also called Communist
   China, in distinction from Nationalist China, the
   government located on the island of Taiwan. Both governments
   claim to represent the entire people of China, but the
   People's republic is recognized as China by the United
   Nationss and most of its member states.

   Syn: Red China, PRC, Beijing.
        [PJC]

WordNet (r) 3.0 (2006):

Communist China
    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]