[thawr-ee-uh, thohr-]

noun Chemistry.

a white, heavy, water-insoluble powder, ThO2, used chiefly in incandescent mantles, as the Welsbach gas mantle.

Origin of thoria

First recorded in 1835–45; thori(um) + -a4
Also called thorium oxide, thorium dioxide. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for thorium dioxide

thorium dioxide


a heavy insoluble white powder used in incandescent mantles. Formula: ThO 2Also called: thoria



another name for thorium dioxide

Word Origin for thoria

C19: thorium + -a, on the model of magnesia
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012