noun.
The principal ore of aluminum, composed mainly of hydrous aluminum oxides and aluminum hydroxides.
The Century Dictionary and Cyclopedia
noun.
A clay found at Les Baux, near Aries in France, and elsewhere, in concretionary grains or oölitic
the GNU version of the Collaborative International Dictionary of English
noun.
A ferruginous hydrate of alumina. It is the most commonly used ore for the preparation of aluminum and alumina. It is also used for the lining of furnaces which are exposed to intense heat.