What is Excusable Homicide?

Legal Definition
Crim. law. The killing of a human being, when the party killing is not altogether free from blame, but the necessity which renders it excusable, may be said to be partly induce by his own act. 1 East, P. C. 220.
-- Bouviers Law Dictionary
Legal Definition
The killing of a human being, either by misadvenfure or in self-defense. U. S. v. King (C. C.) 34 Fed. 306; Slate v. Miller, 9 Houst. (Del.) 564, 32 Atl. 137 ; State v. Reynolds, 42 Kan. 320, 22 Pac. 410, 16 Am. St. Rep. ,483; Hopkinson v. People. 18 111. 265; Bassett v. State, 44 Fla. 2, 33 South. 264. The name itself imports some fault, error, or omission, so trivial, however, that the law excuses it from guilt of felony-, though in strictness it judges it deserving of some little degree of punishment. 4 Bl. Comm. 182. It is of two sorts, either per infortunium, by misadvenfure, or se defendendo, upon a sudden affray. Homicide per infortunium is where a man, doing a lawful act, without any intention of hurt, unfortunately kills another; but, if death ensue from any unlawful act, the offence is manslaughter, and not misadventure. Homicide se defendendo is where a man kills another upon a sudden affray, merely in his own defense, or in defense of his wife, child, parent, or servant, and not from any vindictive feeling. 4 Bl. Comm. 182.
-- Black's Law Dictionary
Legal Definition
A killing in self-defense or by accident. See 9 Houst. (Del.) 542, 33 Atl. 312.
-- Ballentine's Law Dictionary