What is Homicide Se Defendendo?

Legal Definition
Homicide in self-defense ; the killing of a person in self-defense upon a sudden affray, where the slayer had no other possible (or, at least, probable) means of escaping from his assailant. 4 Bl. Comm. 183186; 4 Steph. Comm. 103-105. A species of excusable homicide. Id.; 1 Russ. Crimes, 660.
-- Black's Law Dictionary
Legal Definition
A killing in self-defense.
-- Ballentine's Law Dictionary