from The American Heritage® Dictionary of the English Language, 4th Edition
- n. See thorium dioxide.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The rare earth, thorium oxide.
from the GNU version of the Collaborative International Dictionary of English
- n. A rare white earthy substance, consisting of the oxide of thorium; -- formerly called also thorina.
from The Century Dictionary and Cyclopedia
- n. The name was first given by Berzelius to a supposed new earth announced by him in 1815 as present in xenotime and other Swedish or Norwegian minerals. He afterward proved that this material was in fact yttrium phosphate. In 1828 he discovered a really distinct earth in tine mineral thorite, and applied to it the same name (from the god Thor of Scandinavian mythology), and in this sense the word is used. This earth the oxid of thorium, forms the principal part of the mautles of Welsbach incandescent gas-lamps The material used has been varied, with a view to securing as white a light as possible, but is said to be commonly about 99 per cent. of thorium oxid and 1 per cent of cerium oxid.
- n. An oxid of thorium, ThO2.
From thorium.(American Heritage® Dictionary of the English Language, Fourth Edition)
New Latin. See thorite. (Wiktionary)