melancholy: [14] Etymologically, melancholy means ‘black gall’. The word comes via Old French melancolie and late Latin melancholia from Greek melagkholíā, a compound formed from mélās ‘black’ (source also of English melanin [19] and melanoma [19]) and kholé ‘bile’ (a relative of English gall). This ‘black bile’ was one of the four bodily substances or ‘humours’ whose relative preponderance, according to medieval medical theory, determined a person’s physical and mental state. Excess of black bile was thought to cause depression – hence the modern meaning of melancholy. => gall, melanoma[melancholy etymology, melancholy origin, 英语词源]