The Collaborative International Dictionary
Gadolinia
Gadolinia \Gad`o*lin"i*a\, n. [NL. See Gadolinite.] (Chem.) A rare earth associated with yttria and regarded as the oxide ( Gd2O3) of a metallic element, gadolinium.
Wiktionary
gadolinia
n. (context inorganic compound English) The rare earth gadolinium oxide