the.com/melancholia

means A deep, lingering sadness or gloom — often with no single obvious cause, more mood than event.

from From Greek melas (black) + khole (bile), one of the four humors ancient and medieval medicine believed governed health and temperament. Too much black bile, physicians claimed, made a person broody, pensive, sunk in gloom — so the word named both the fluid and the mood it supposedly caused. The theory is long dead, but the word outlived the biology, drifting from medical diagnosis into the looser, more literary sadness we mean today.