terbium
/ˈtəːbɪəm
/noun [mass noun]
The chemical element of atomic number 65, a silvery-white metal of the lanthanide series. (Symbol: Tb) Green light is also emitted from some lanthanide elements: lanthanum, cerium, and terbium.
Origin
Mid 19th century: modern Latin, from Ytterby, the name of a village in Sweden where it was discovered. Compare with erbium and ytterbium.