a) a soft, earthy, white clay used in the manufacture of porcelain.
Kaolin is an experimental 32-bit operating system for the x86 architecture, serving as the "clay" before the development of the adx operating system. Although it is meant to be a fully-fledged operating system; including a bootloader, monolithic kernel, tooling and more, it exists as a trial run for Nouveau's operating system development before the adx operating system is developed with the adx language.
Documentation for kaolin can be found here
