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

Stringer built most of the studio’s interior himself, save for select furnishings and an Ikea shelving unit he painted cobalt blue to match the room’s colorful aesthetic.

From Los Angeles Times ● Sep. 25, 2025

The brothers themselves appeared in court via a video feed from a San Diego prison, wearing identical cobalt blue prison uniforms.

From BBC ● Apr. 17, 2025

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

There’s a distinct difference between periwinkle and cobalt blue.

From "Monday's Not Coming" by Tiffany D. Jackson