Source : Webster's Revised Unabridged Dictionary (1913)

Kaolin \Ka"o*lin\, Kaoline \Ka"o*line\, n. [Chin. kao-ling.]
   (Min.)
   A very pure white clay, ordinarily in the form of an
   impalpable powder, and used to form the paste of porcelain;
   China clay; porcelain clay. It is chiefly derived from the
   decomposition of common feldspar.

   Note: The name is now applied to all porcelain clays which
         endure the fire without discoloration.

Source : WordNet®

kaolin
     n : a fine usually white clay formed by the weathering of
         aluminous minerals (as feldspar); used in ceramics and as
         an absorbent and as a filler (e.g., in paper) [syn: {china
         clay}, {china stone}, {kaoline}, {porcelain clay}, {terra
         alba}]