a hard ferromagnetic silver-white bivalent or trivalent metallic element; a trace element in plant and animal nutrition
"The soil was enriched with cobalt to serve as an essential trace element for the growth of cattle."
A chemical element (symbol Co) with an atomic number of 27: a hard, lustrous, silver-gray metal.
"The factory processed cobalt to create durable alloys used in high-performance jet engines."
In plain English: Cobalt is a shiny, blue-colored metal that scientists use to make strong magnets and special paints.
"The new blue paint contains cobalt to make the color deeper and richer."
Usage: Avoid confusing the spelling of this metal with "cobalt," which refers to a type of blue pigment or dye. In technical contexts, always use the chemical symbol Co rather than abbreviating it as Cob when writing formulas.
A village in Connecticut
"The residents of Cobalt gathered at the town hall to discuss the new road repairs."
The name cobalt comes from the German word Kobalt, which is related to Kobold (goblin). Early silver miners in the Harz Mountains used this term for a toxic rock containing arsenic and sulfur because it ruined ore and made workers sick.