1
: a magnetic metallic element that is used especially in alloys, in batteries, and as a pigment in paint and glass see Chemical Elements Table
2

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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

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The recycled cathode active materials include lithium, nickel, cobalt and manganese. Prabhat Ranjan Mishra, Interesting Engineering, 19 Sep. 2026 For Washington, strategic minerals are a key battleground with Beijing, which dominates refining for critical materials like lithium, cobalt and nickel. Alfie Pannell, Miami Herald, 9 Sep. 2026 Comprising fuchsia, crimson, and cobalt, the work depicts a scene inspired by One Thousand and One Nights, a renowned collection of Middle Eastern folklore. Kara Jillian Brown, InStyle, 9 Sep. 2026 Dazzling in majolica tile, the Santa Maria Assunta catches the sunlight in ribbons of green, gold, and cobalt—an architectural wonder shimmering above the sea. Condé Nast, Condé Nast Traveler, 3 Sep. 2026 See All Example Sentences for cobalt

Word History

Etymology

German Kobalt, alteration of Kobold, literally, goblin, from Middle High German kobolt; from its occurrence in silver ore, believed to be due to goblins

First Known Use

circa 1872, in the meaning defined at sense 1

Time Traveler
The first known use of cobalt was circa 1872

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Cite this Entry

“Cobalt.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/cobalt. Accessed 21 Sep. 2026.

Kids Definition

: a tough shiny silver-white magnetic metallic element that is found with iron and nickel and is used especially in alloys see element
Etymology

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

: a tough lustrous silver-white magnetic metallic element that is related to and occurs with iron and nickel and is used especially in alloys
symbol Co
see Chemical Elements Table

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