cobalt blue

American  

noun

1. a deep blue to a strong greenish-blue color.

2. any of a number of pigments containing an oxide of cobalt.

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cobalt blue British  

noun

1. Also called: Thénard's blue.  any greenish-blue pigment containing cobalt aluminate, usually made by heating cobaltous sulphate, aluminium oxide, and phosphoric acid together

2. 1. a deep blue to greenish-blue colour

   2. ( as adjective )

      a cobalt-blue car

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Etymology

Origin of cobalt blue

First recorded in 1825–35

Compare meaning

How does cobalt-blue compare to similar and commonly confused words? Explore the most common comparisons:

• cobalt blue vs. royal blue

Example Sentences

See Examples For:

cobalt blue

The blue-tinted lenses seemed to resonate perfectly with the cobalt blue background of the Davos stage, creating a striking effect.

From The Wall Street Journal ● Jan. 22, 2026

Shasta with puffy white clouds drifting across a cobalt blue sky, Griffin recalled one of his worst days on the job.

From Los Angeles Times ● Apr. 21, 2025

At New York Fashion week, coloured mascara was all the rage and the cobalt blue mascara was a particular stand out at LaQuan Smith's catwalk.

From BBC ● Sep. 11, 2024

If the new regulation was cobalt blue and the regulation back then was sky blue, that would not cut it—the government was out of luck.

From Slate ● Jul. 22, 2024

The club itself was a massive cobalt blue sphere, three kilometers in diameter, floating thirty meters off the ground.

From "Ready Player One: A Novel" by Ernest Cline