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

The solution is to add a dose of “heavy” rare earths, which have names like dysprosium and terbium and which allow the magnet to keep working when it gets hot.

From The Wall Street Journal • Jun. 2, 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

Visited this month by AFP, the southeastern mining region of Ganzhou -- which specialises in "heavy" rare earths including yttrium and terbium -- was a hive of activity.

From Barron's • Nov. 26, 2025

Rare earths, like samarium and terbium, are critical to the production of technologies set to shape the world in the coming decades – including electric vehicles and highly advanced weapons systems.

From BBC • Apr. 25, 2025

Er�bium, a rare metal found along with yttrium, terbium, and other rare elements in some rare minerals.

From The New Gresham Encyclopedia Volume 4, Part 2: Ebert to Estremadura by Various