Noun
Oxide of thulium.
Source: Webster's dictionaryIn 1879, Swedish chemist Per Theodor Cleve separated in the rare earth erbia another two previously unknown components, which he called holmia and thulia : these were the oxides of holmium and thulium respectively. Source: Internet
This oxide is sometimes called "thulia". citation Reddish-purple thulium(II) compounds can be made by the reduction of thulium(III) compounds. Source: Internet