In Greek, whose color lexicon did not stabilize for many centuries, the words most commonly used for blue are glaukos and kyaneos. The latter probably referred originally to a mineral or a metal; it has a foreign root and its meaning often shifted. During the Homeric period it denoted both the bright blue of the iris and the black of funeral garments, but never the blue of the sky or sea. An analysis of Homer’s poetry shows that out of sixty adjectives describing elements and landscapes in the Iliad and Odyssey, only three are color terms, while those evoking light effects are quite numerous. During the classical era, kyaneos meant a dark color: deep blue, violet, brown, and black. In fact, it evokes more the “feeling” of the color than its actual hue. The term glaukos, which existed in the Archaic period and was much used by Homer, can refer to gray, blue, and sometimes even yellow or brown. Rather than denoting a particular color, it expresses the idea of a color’s feebleness or weak concentration. For this reason it is used to describe the color of water, eyes, leaves, or honey.
Michel Pastoureau, Blue: The History of a Color (via emmaylor)
"Glaucous" means pale blue/green/grey-ish and waxy — when I look it up in English it seems mostly be used to describe feathers, leaves, the powdery-waxy natural coating on fruit like plums and grapes. Which is interesting because in French, "glauque" also means "mordid, depressing, sinister." (Actually, when I think about it, the French word tends to be used synaesthetically. "Glauque" is what you might use to describe corpses’ eyes or the paint on prison walls.)