Definitions

1. noun

A blue-grey chemical element that is a transition metal, used in paint, ceramics, magnets, and batteries.

“The artist chose cobalt blue for the background of her painting.”

2. noun

A deep blue colour with a purplish tint, as of a clear sky on a sunny day.

“The cobalt sky reflected the beauty of nature.”

3. adjective

Relating to or containing cobalt, or having a cobalt-like colour.

“Cobalt blue glassware is highly prized by collectors.”