D defs.my
Entry 1 sense Webster, 1913

Thulium

/thū'lēəm/ · Thu·li·um · IPA /ˈθjuːliəm/
01 n. A rare metallic element of the lanthanide group having atomic number 69, and atomic weight 168.93. It is found in the mineral gadolinite a…
  1. 1.
    A rare metallic element of the lanthanide group having atomic number 69, and atomic weight 168.93. It is found in the mineral gadolinite and other minerals, together with other rare earths.(Chem.)