thorium (n.) Look up thorium at Dictionary.com
rare metallic element, 1832, Modern Latin, named by its discoverer, Swedish chemist Jöns Jakob Berzelius (1779-1848) from thorite (silicate of thorium), the name of a mineral found in Norway from which it was extracted (which Berzelius also had named, as thoria, in 1828), and named in honor of the Scandinavian god Thor. With metallic element ending -ium.