In ancient and medieval physiology and medicine: the humour choler in a form having a dark or black colour; (also) the humour melancholy (in a normal or abnormal form). Also called atrabile. Compare slightly earlier black cholera , and later "black bile".
Late Middle English; earliest use found in Guy de Chauliac's Grande Chirurgie. From black + choler, after post-classical Latin cholera nigra.