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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Klein Blue made a striking statement at Bottega Veneta in a textured look, while Jil Sander, Givenchy, Dries Van Noten, and Lii used flashes of cobalt to punch up a more neutral palette. Andrea Zendejas, Vogue, 21 Aug. 2026 This sintering method produced a tough bulk composite where diamond grains are held inside a continuous cubic boron nitride structure, with cobalt spread throughout the material. Aman Tripathi, Interesting Engineering, 20 Aug. 2026 Those gaps, the researchers argue, could have been filled by chemical reactions catalyzed by metals in the vent systems such as nickel, iron, cobalt and palladium. Philip Ball, Scientific American, 20 Aug. 2026 The 180 kilograms of cobalt could be recovered from an asteroid about 3 to 6 meters across. Scott K. Johnson, ArsTechnica, 20 Aug. 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 24 Aug. 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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