small wild plant with purplish-blue flowers, c. 1300, from Old French violete (12c.), diminutive of viole "violet," from Latin viola "the violet, a violet color," cognate with Greek ion (see iodine), probably from a pre-Indo-European substrate Mediterranean language. The color sense (late 14c.) developed from the flower.
an English notion of a stereotypical French oath, 1869, from French sacré bleu, literally "holy blue," a euphemism for sacré Dieu (1768), "holy God." From Old French sacrer, from Latin sacrare "to make or declare sacred" (see sacred). Such things are never idiomatic. In an old French-language comic set in the U.S. Wild West, the angry cowboys say "Bloody Hell!"
1680s as the name of a type of steel-gray metal, from German kobold "household goblin" (13c.), which became also a Harz Mountains silver miners' term for rock laced with arsenic and sulfur (according to OED so called because it degraded the ore and made the miners ill), from Middle High German kobe "hut, shed" + *holt "goblin," from hold "gracious, friendly," a euphemistic word for a troublesome being.
The metallic element (closely resembling nickel but much rarer) was extracted from this rock. It was known to Paracelsus, but discovery is usually credited to the Swede George Brandt (1733), who gave it the name. Extended to a blue color 1835 (a mineral containing it had been used as a blue coloring for glass since 16c.). Compare nickel. Related: Cobaltic; cobaltous.
"water," late 14c., from Latin aqua "water; the sea; rain," from PIE root *akwa- "water." Used in late Middle English in combinations from old chemistry and alchemy to mean "decoction, solution" (as in aqua regia, a mix of concentrated acids, literally "royal water," so called for its power to dissolve gold and other "noble" metals). As the name of a light greenish-blue color, 1936.