What does "clay" mean?

Additional senses

1. 2.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 mill. -- 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, bole, etc. -- Fire clay , a variety of clay, entirely free from lime, iron, or an alkali, and therefore infusible, and used for fire brick. -- 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.
2. 3.To cover or manure with clay.
3. 4.To clarify by filtering through clay, as sugar.