The color azure ultimately takes its name from the intense blue mineral lapis lazuli. Lapis is the Latin word for "stone" and lāzulī is the genitive form of the Medieval Latinlāzulum, which is taken from the Arabic لازورد lāzaward, itself from the Persian لاژورد lāžaward, which is the name of the stone in Persian and also of a place where lapis lazuli was mined. The name of the stone came to be associated with its color. The Frenchazur, the Italianazzurro, the Polishlazur, Romanianazur and azuriu, the Portuguese and Spanishazul, Hungarianazúr, and the Catalanatzur, all come from the name and color of lapis lazuli. The word was adopted into English from the French, and the first recorded use of it as a color name in English was in 1374 in Geoffrey Chaucer's work Troilus and Criseyde, where he refers to "a broche, gold and asure". Azure also describes the color of the mineral azurite, both in its natural form and as a pigment in various paint formulations. In order to preserve its deep color, azurite was ground coarsely. Fine-ground azurite produces a lighter, washed-out color. Traditionally, the pigment was considered unstable in oil paints, and was sometimes isolated from other colors and not mixed. The use of the term spread through the practice of heraldry, where "azure" represents a blue color in the system of tinctures. In engravings, it is represented as a region of parallel horizontal lines, or by the abbreviation az. or b. In practice, azure has been represented by any number of shades of blue. In later heraldic practice a lighter blue, called bleu celeste, is sometimes specified.
According to the logic of the :File:RBG color wheel.svg|RGB color wheel, indigo colors are those colors with hue codes between 255 and 225, azure colors are those colors with hue codes between 195 and 225, and cyan colors are those colors with hue codes between 165 and 195. Another way of describing it could be that cyan is a mixture of blue and green light, azure is a mixture of blue and cyan light, and indigo is a mixture of blue and violet light. All of the colors shown below in the section shades of azure are referenced as having a hue between 195 and 225 degrees, with the exception of the very pale X11web color azure - RGB - which, with a hue of 180 degrees, is a tone of cyan, but follows the artistic meaning of azure as sky blue.
Côte d'Azur is a name commonly used for the French Riviera, part of France's southeastern coast on the Mediterranean.
In Chinese mythology, the Azure Dragon is one of the Four Symbols of the Chinese constellations. It is sometimes called the Azure Dragon of the East. Known as Seiryū in Japan and Cheongryong in Korea, it represents the east and the spring season.