Black's Law Dictionary (2nd edition)dictionaries

Mitigation

Alleviation; abatement or diminution of a penalty or punishment Imposed by law. “Mitigating circumstances” are such as do not constitute a justification or excuse of the offense in question, but which, in fairness and mercy, may be considered as extenuating or reducing the degree of moral culpability. See Heaton v. wright, 10 How. Prac. (N. Y.) 82; wandell v. Ed-wards, 25 Hun (N. Y.) 500; Hess v. New York Press Co., 26 App. Div. 73, 49 N. Y, Supp. 894

Source: Black’s Law Dictionary 2nd Ed (1910)