c.1300, "condition characterized by sullenness, gloom, irritability," from O.Fr. melancholie, from L.L. melancholia, from Gk. melankholia "sadness," lit. "black bile," from melas (gen. melanos) "black" (see melanin) + khole "bile" (see Chloe). Medieval physiology attributed depression to excess of "black bile," a secretion of the spleen and one of the body's four "humors." Adj. sense of "sullen, gloomy" is from 1526; sense of "deplorable" (of a fact or state of things) is from 1710.