cobalt
Americannoun
noun
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A silvery-white, hard, brittle metallic element that occurs widely in metal ores. It is used to make magnetic alloys, heat-resistant alloys, and blue pigment for ceramics and glass. Atomic number 27; atomic weight 58.9332; melting point 1,495°C; boiling point 2,900°C; specific gravity 8.9; valence 2, 3.
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See Periodic Table
Etymology
Origin of cobalt
1675–85; < German Kobalt, variant of Kobold kobold
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Explanation
Cobalt is a silvery-gray metal. It's also the name of a deep blue pigment that's made from cobalt. Cobalt, mined from the earth's crust along with copper and nickel, has a shiny appearance with a slightly bluish tint. Chemically combining cobalt with aluminum oxide results in the blue pigment that's been familiar to artists for centuries. Cobalt blue is the blue in very old Chinese blue-and-white porcelain, and it features in paintings by Monet and van Gogh. Cobalt is from the German kobold, "household goblin," a nickname miners gave arsenic-laced ore that made them sick.
Vocabulary lists containing cobalt
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Backed by more than $2.7 billion in pledged investment, the corridor is meant to move copper and cobalt, vital to the energy transition.
From Barron's • May 7, 2026
LAR has also transported cobalt, packaged in one-tonne bags, and could carry other minerals either in bulk or packaged form.
From Barron's • May 7, 2026
The US is also negotiating a minerals deal with DR Congo to help gain access to the central African country's vast reserves of key metals such as cobalt, tantalum, lithium and copper.
From BBC • Apr. 6, 2026
About $250 million to $300 million in capital expenditure is still needed to finish infrastructure upgrades and increase production to 75,000 tons of copper and 15,000 tons of cobalt annually, according to Powch.
From The Wall Street Journal • Mar. 31, 2026
They were cobalt blue, purple from manganese, yellow from copper, red, and a green which was also got from copper.
From "The Once and Future King" by T. H. White
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
