What is Blood Money?

Legal Definition
Blood money, also called bloodwit, is money or some sort of compensation paid by an offender (usually a murderer) or his/her family group to the family or kin group of the victim.
-- Wikipedia
Legal Definition
A weregild or pecuniary mulct paid by a slayer to the relatives of his victim. Also used, in a popular sense, as descriptive of money paid by way of reward for the apprehension and conviction of a person charged with a capital crime.
-- Black's Law Dictionary
Legal Definition
The price paid to cause one’s death.
-- Ballentine's Law Dictionary