- cyanosis (n.)
- "blue disease," the "blue jaundice" of the ancients, 1820, Medical Latin, from Greek kyanosis, from kyanos "dark blue color" (see cyan) + -osis.
- cyanotic (adj.)
- 1833, from comb. form of root of cyanosis + -ic.
- cyanogen
- "A colourless flammable highly poisonous gas made by oxidizing hydrogen cyanide", Early 19th century: from French cyanogène, from Greek kuanos 'dark blue mineral' + -gène (see -gen), so named because it is a constituent of Prussian blue.