Webster’s Revised Unabridged Dictionary · 1913
Kaolin
Ka′o·lin, 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.
☞ The name is now applied to all porcelain clays which endure the fire without discoloration.