terbium

American  

[tur-bee-uhm] / ˈtɜr bi əm /

noun

Chemistry.

1. a rare-earth, metallic element present in certain minerals and yielding colorless salts. Tb; 65; 158.924; 8.25.

---

terbium British  

/ 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

---

terbium Scientific  

/ tûr′bē-əm /

1. A soft, silvery-gray metallic element of the lanthanide series. It is used in color television tubes, x-ray machines, and lasers. Atomic number 65; atomic weight 158.925; melting point 1,356°C; boiling point 3,123°C; specific gravity 8.229; valence 3, 4.

2. See Periodic Table

---

Other Word Forms

Derived Forms

• terbic
  adjective

Etymology

Origin of terbium

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

Example Sentences

Northern Minerals owns the Browns Range project in Western Australia, a potential source of heavy rare earths dysprosium and terbium that are today mostly produced by China.

From The Wall Street Journal • May 19, 2026

Geological Survey geologists first identified rare earth mineralization in the Music Valley area in 1954, with sampling reporting enrichment in dysprosium, terbium, yttrium and ytterbium, Dateline Resources said in a press release.

From Los Angeles Times • Mar. 30, 2026

So, it has surpluses of lighter rare earths such as neodymium, but lacks extractable quantities of heavier elements like dysprosium and terbium, which are critical for many high-performance magnets.

From BBC • Jan. 15, 2026

Heavy rare-earth elements include dysprosium, terbium, holmium, erbium, thulium, ytterbium, lutetium, and yttrium.

From Barron's • Nov. 13, 2025

Who, then, will be the first to discover a use for indium, germanium, terbium, thulium, lanthanum, neodymium, scandium, samarium and others as unknown to us as tungsten was to our fathers?

From Creative Chemistry Descriptive of Recent Achievements in the Chemical Industries by Slosson, Edwin E.