homicide, in law, the taking of human life. Homicides that are neither justifiable nor excusable are considered crimes. A criminal homicide committed with malice is known as murder, otherwise it is called manslaughter. A homicide is excusable if it is the result of an accident that occurred during a lawful act and that did not amount to criminal negligence. Justifiable homicides are intentional killings done in accordance with legal obligation, or in circumstances where the law recognizes no wrong. They include the execution of criminals in some states, killings necessary to prevent a felony or to arrest a suspected felon, and killings in self-defense. In some states of the United States, one may lawfully kill in resisting the unlawful invasion of a home or real property. Many states make a distinction between first and second degree murders. First degree murder is a homicide committed with deliberately premeditated malice, or with extreme and wanton malice. The conviction for first degree murder often carries a sentence of life imprisonment; in some states it can be punished by execution. Second degree murder is a lesser crime, in which a homicide is committed with malice but without deliberation or premeditation.

Killing of one human being by another. Homicide is a general term; it includes murder, manslaughter, and other criminal homicides as well as noncriminal killings. Murder is the crime of intentionally and unjustifiably killing another. In the U.S., first-degree murder is a homicide committed with premeditation or in the course of a serious felony (e.g., kidnapping). Second- and third-degree murder involve lesser degrees of intent. Manslaughter is commonly divided into voluntary (or first-degree) and involuntary (or second- and third-degree) manslaughter. The first type encompasses any homicide resulting from an intentional act done without malice or premeditation and while in the heat of passion or on sudden provocation; the second type is variously defined in different jurisdictions but often includes an element of unlawful recklessness or negligence. Noncriminal homicides include killings committed in defense of oneself or another and deaths resulting from accidents caused by persons engaged in lawful acts. Seealso felony and misdemeanour; self-defense.

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