wasium

from The Century Dictionary.

• noun A supposed new chemical element announced in 1862 by Bahr as present in a Swedish mineral resembling orthite. Its supposed oxid was probably thoria, though it may have been a mixture of earths of the yttria and ceria groups.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Chem.) A rare element supposed by Bahr to have been extracted from wasite, but now identified with thorium.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun chemistry, archaic A supposed chemical element extracted from wasite, later identified as thorium.