Definition of cobalt in English:

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Pronunciation: /ˈkōˌbôlt/


1The chemical element of atomic number 27, a hard silvery-white magnetic metal. (Symbol: Co)
Example sentences
  • This packing arrangement is also observed for many metals, including rubidium, osmium, cobalt, zinc, and cadmium.
  • Besides gold and diamonds, the area is rich in copper, uranium, palladium and cobalt, as well as coltan ore.
  • The slow growth rate is thought to enhance the absorption of heavy metals like copper and cobalt from sea water.
1.1 short for cobalt blue. [as modifier]: a cobalt sky
More example sentences
  • He muttered something in angry fluent French, as he tilted his head back and looked up at the star-dusted cobalt sky.
  • It was February with cobalt skies, snappy air, and a fresh blanket of snow.
  • This past week in the forest park, the fiery foliage set against cobalt skies was a sight to behold.

Cobalt is chiefly obtained as a byproduct from nickel and copper ores. It is a transition metal similar in many respects to nickel. Its main use is as a component of magnetic alloys and those designed for use at high temperatures.



Pronunciation: /kōˈbôltik/
Example sentences
  • Hydrated cobalt oxide or cobaltic hydroxide is produced by adding sodium hydroxide to this solution.
  • An opportunity might have been lost for guiding mining operations to the working of any payable cobaltic vein.
  • The cobaltic complex has also been synthesized by metal exchange from previously obtained sodium ascorbate and cobaltic dichloride hexahydrate in aqueous medium.


Pronunciation: /kōˈbôltəs/
Example sentences
  • We produce 300 tons of cobalt oxide and 180 tons of cobaltous oxide yearly, one of the largest production and sale bases in China.


Late 17th century: from German Kobalt 'imp, demon' (because the presence of cobalt-bearing ore made it more difficult to extract silver, and miners believed that it was harmful to the silver ore with which it occurred).

  • Cobalt is a hard silvery-white magnetic metal, often found in the ground alongside deposits of silver. The name comes from German Kobalt, a variation of the word Kobold meaning ‘goblin or demon’, and perhaps related to goblin. Medieval silver miners gave the metal this name because of the trouble it caused them. They believed that cobalt was harmful both to the silver ores with which it occurred and to their own health, though these effects were mainly due to the arsenic and sulphur with which it was frequently combined.

For editors and proofreaders

Syllabification: co·balt

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