Azure is a bright, clear blue color, like the color of the sky on a perfect sunny day when there isn't a single cloud in sight. When poets describe “azure skies” or “azure seas,” they're painting a picture of the most beautiful, pure blue you can imagine.

The word comes from the name of a semi-precious stone called lapis lazuli, which was ground into powder to make a brilliant blue paint in medieval times. This paint was so expensive that artists saved it for painting the most important parts of their work, like the robes of important figures in religious paintings.

Today, azure appears in many contexts. Computer scientists at Microsoft named their cloud computing service Azure. The French Riviera, a beautiful coastline in southern France, is called the Côte d'Azur, which means “Azure Coast,” because of its stunning blue waters. When you see the word azure in a story or poem, the writer is usually trying to convey not just any blue, but the most vivid, perfect blue imaginable.