"blue disease," the "blue jaundice" of the ancients, 1820, Medical Latin, from Greek kyanosis, from kyanos "dark blue color" (see cyan) + -osis. Also cyanopathy. It is caused by imperfect circulation and oxygenation of the blood.
"greenish-blue color," 1889, short for cyan blue (1879), from Greek kyanos "dark blue, dark blue enamel, lapis lazuli," probably a non-Indo-European word, but perhaps akin to, or from, Hittite *kuwanna(n)- "copper blue."
word-forming element expressing state or condition, in medical terminology denoting "a state of disease," from Latin -osis and directly from Greek -osis, formed from the aorist of verbs ending in -o. It corresponds to Latin -atio.