The Collaborative International Dictionary of English v.0.48:
Clay \Clay\ (kl[=a]), n. [AS. cl[=ae]g; akin to LG. klei, D.
klei, and perh. to AS. cl[=a]m clay, L. glus, gluten glue,
Gr. gloio`s glutinous substance, E. glue. Cf. Clog.]
1. A soft earth, which is plastic, or may be molded with the
hands, consisting of hydrous silicate of aluminium. It is
the result of the wearing down and decomposition, in part,
of rocks containing aluminous minerals, as granite. Lime,
magnesia, oxide of iron, and other ingredients, are often
present as impurities.
2. (Poetry & Script.) Earth in general, as representing the
elementary particles of the human body; hence, the human
body as formed from such particles.
I also am formed out of the clay. --Job xxxiii.
The earth is covered thick with other clay,
Which her own clay shall cover. --Byron.
Bowlder clay. See under Bowlder.
Brick clay, the common clay, containing some iron, and
therefore turning red when burned.
Clay cold, cold as clay or earth; lifeless; inanimate.
Clay ironstone, an ore of iron consisting of the oxide or
carbonate of iron mixed with clay or sand.
Clay marl, a whitish, smooth, chalky clay.
Clay mill, a mill for mixing and tempering clay; a pug
Clay pit, a pit where clay is dug.
Clay slate (Min.), argillaceous schist; argillite.
Fatty clays, clays having a greasy feel; they are chemical
compounds of water, silica, and aluminia, as halloysite,
Fire clay, a variety of clay, entirely free from lime,
iron, or an alkali, and therefore infusible, and used for
Porcelain clay, a very pure variety, formed directly from
the decomposition of feldspar, and often called kaolin.
Potter's clay, a tolerably pure kind, free from iron.