Definition:

Porcelain (noun) is a high-fired, vitrified[link] clay body consisting of kaolin, silica, and one or more fluxes. Ball clay is sometimes added to increase plasticity during forming. The total clay content must be under 50% to be considered true porcelain. The clay body will fire to a white or off-white color and may be translucent where the wall is thin.

Examples: A porcelain clay body is usually stiff and hard to throw.

Aging helps increase porcelain's plasticity. (adjective and noun)