terbium

UK: /ˈtɜːbɪəm/ US: (tûr′bē əm)

WordReference Random House Unabridged Dictionary of American English © 2026

ter•bi•um  (tûr′bē əm), n. [Chem.]

1. Chemistry a rare-earth, metallic element present in certain minerals and yielding colorless salts. Symbol: Tb;
   at. no.: 65;
   at. wt.: 158.924;
   sp. gr.: 8.25.

• (Yt)terb(y), name of Swedish town where found + -ium. See ytterbium 1835–45

ter′bic, adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

terbium / ˈtɜːbɪəm/ noun

1. a soft malleable silvery-grey element of the lanthanide series of metals, occurring in gadolinite and monazite and used in lasers and for doping solid-state devices. Symbol: Tb; atomic no: 65; atomic wt: 158.92534; valency: 3 or 4; relative density: 8.230; melting pt: 1356°C; boiling pt: 3230°C

Etymology: 19th Century: from New Latin, named after Ytterby, Sweden, village where it was discovered

ˈterbic adjective