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The metallic element "cobalt" ultimately draws its name from folklore. In Middle High German, "kobolt" denoted a usually helpful household elf that engaged in nasty pranks only when it was offended. Later, early Modern German Kobold came to refer to a variety of less helpful goblins inhabiting fields and mountains. The variant "Kobolt" in the 16th century was applied by German miners to ores containing the metal cobalt, which they considered to be worthless; they believed that mountain goblins had spoiled adjacent silver ores, or had stolen the silver within the ore. The metal itself in relatively pure form was not produced and described until the 17th century, when "cobalt," with its first letter influenced by New Latin cobaltum, became part of the international language of science.
Examples of cobalt in a Sentence
Tiisetso Motsoeneng, semafor.com, 4 May 2026
Lithium ion batteries that contain nickel, magnesium and cobalt (NMC), which are used in many smartphones, can be prone to overheating and catching fire, according to the National Fire Protection Association.
—Sofi Zeman
may 2, Kansas City Star, 2 May 2026
In another building, GM is building LMR (Lithium Manganese-Rich) batteries that have less energy density but cost less and use fewer rare minerals, like cobalt.
—Kristin Shaw, Popular Science, 30 Apr. 2026
In some parts of the world, rivers near cobalt and copper mines have become so acidic that communities can no longer drink water from them.
—Abraham Nunbogu, Fortune, 29 Apr. 2026
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Cite this Entry
“Cobalt.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/cobalt. Accessed 5 May. 2026.
Copy CitationKids Definition
from German Kobalt "cobalt," an altered form of Kobold, literally, "goblin"; so called because its appearance in silver ore was thought to have been the work of goblins who left it in place of silver which they stole
Medical Definition
cobalt
noun
