cobalt
Americannoun
noun
-
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.
-
See Periodic Table
Etymology
Origin of cobalt
1675–85; < German Kobalt, variant of Kobold kobold
Compare meaning
How does cobalt compare to similar and commonly confused words? Explore the most common comparisons:
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.
Both the Lubber Fiend and Cobalt believe more practical help should be available to club venues.
From BBC • Mar. 28, 2026
Prospect Lithium Zimbabwe, owned by Zhejiang Huayou Cobalt, has spent $400 million on a processing plant that should be operational in the coming weeks, its representative Patience Chizodza told state broadcaster ZBC.
From Barron's • Feb. 26, 2026
The company said the Azure Cobalt 100 central processing unit, the software giant’s first in-house processor, is available in preview starting Tuesday for customers of the Azure cloud-computing service.
From Seattle Times • May 21, 2024
Cobalt extraction creates hazardous working conditions and generates toxic waste that contaminates land, air, and water surrounding the mines.
From Science Daily • Jan. 18, 2024
“And you didn’t kill a Cobalt Blue Orchid, sweetie.”
From "The Science of Breakable Things" by Tae Keller
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.
