Ter"bi*um (?), n. [NL., fr. Ytterby, in Sweden. See Erbium.] (Chem.) A rare metallic element, of uncertain identification, supposed to exist in certain minerals, as gadolinite and samarskite, with other rare ytterbium earth. Symbol Tr or Tb. Atomic weight 150.

Ter"bi*um (?), n. [NL., fr. Ytterby, in Sweden. See Erbium.] (Chem.) A rare metallic element, of uncertain identification, supposed to exist in certain minerals, as gadolinite and samarskite, with other rare ytterbium earth. Symbol Tr or Tb. Atomic weight 150.

• a metallic chemical element (symbol Tb) with an atomic number of 65.
  

German
• terbium