deep blue; sky blue; azure.
Heraldry. a sky-blue tincture, used especially on the Continent.
a deep blue colour; azure
(as adjective): a cerulean sea
1660s, with -an + Latin caeruleus “blue, dark blue, blue-green,” perhaps dissimilated from caelulum, diminutive of caelum “heaven, sky,” of uncertain origin (see celestial). The Latin word was applied by Roman authors to the sky, the Mediterranean, and occasionally to leaves or fields. As a noun, from 1756.
a light-blue to strong greenish-blue color. a pigment used in painting consisting mainly of oxides of tin and cobalt, chiefly characterized by its greenish-blue color and permanence.
a North American wood warbler, Dendroica cerulea, the male of which is blue above and white below.
cerulein ce·ru·le·in (sə-rōō’lē-ən) n. A decapeptide that stimulates smooth muscle, especially gallbladder contraction, and increases digestive secretions.
a serum glycoprotein involved in the storage and transport of copper and iron. ceruloplasmin ce·ru·lo·plas·min (sə-rōō’lō-plāz’mĭn) n. A blue, copper-containing globulin that may play a part in erythropoiesis and oxygen reduction.