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.

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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

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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

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Other Word Forms

• terbic adjective

Etymology

Origin of terbium

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

Example Sentences

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

Rare earth elements are mentioned in 17 licences, with more permits referencing specific rare earths such as cerium or terbium.

From Barron's • Feb. 14, 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

Certain powerful types of rare-earth magnets—often used for car engines, robotics and industrial machinery—typically use small quantities of dysprosium and terbium, two “heavy” rare-earth elements, to allow magnets to function at high temperatures.

From The Wall Street Journal • Dec. 2, 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