melan(o)-

Black.

Greek melas, melan‑, black.

Most examples occur in medical contexts, such as melanin, a dark brown to black pigment that is responsible for tanning; a melanocyte (Greek kutos, vessel) is a mature melanin-forming cell, typically in the skin; a melanoma is a tumour of such cells; melatonin is a hormone which inhibits melanin formation and is thought to be concerned with regulating the reproductive cycle. Melancholy derives from Greek kholē, bile, since an excess of black bile, one of the four humours of ancient medicine, was thought to cause depression.