Both are, by definition, homicide
S: (n)
homicide (the killing of a human being by another human being)
Care to explain the difference?
The probem with the definition you use is that one can use this to say someone protecting themselves by killing their attacker is commiting homicide.
They are. By definition.
Also to say a woman that gets an abortion because her life is in danger if she continues the pregnancy is saying she is commiting homicide by protecting herself.
She is. By definition.
So when is 'the killing of a human being by another human being' NOT homicide?
Never. That's the ******* definition of homicide, you illiterate twit.
Name calling will NOT make you look any more smarter.
And by definition it may be homicide however it would be called 'Non-criminal homicide'. The way you are trying to make it look is that homicide is a criminal act no matter how you look at it. To post a word and then a 'short' definition is misleading expecally the way you did it. The homicide you are trying to say abortion is would be 'Criminal homicide'
But, if you want to get even more technical, of which you seem to like to do, then even 'Criminal homicide' would not work in the case of abortion. Seeing that abortion is not illegal it can not be considered 'Criminal homicide'. It could however be considered 'State-sanctioned homicide' due to the fact that the laws on abortion are made by the states. If the woman is in danger like I said before then it can be considered 'Non-criminal homicide'. If she is not in danger then it is a different kind of homicide.
Next time you may try to explain what it is you are really refering to a bit better. Posting a word and only one part of the definition makes YOU look like the illiterate one.

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Non-criminal homicide: Homicides do not always involve a crime. Sometimes the law allows homicide by allowing certain defenses to criminal charges. One of the most recognized is self defense, which provides that a person is entitled to commit homicide to protect his or her own life from a deadly attack. For example, if a police officer confronts a suspect armed with a dangerous or deadly weapon, the officer may use force to stop the suspect. If this force ends up killing the suspect it is still considered a homicide, which in this case, is not illegal under Tennessee v. Garner.
State-sanctioned homicide: Homicides may also be non-criminal when conducted with the sanction of the state. The most obvious example is capital punishment, in which the state determines that a person should die. Homicides committed in action during war are usually not subject to criminal prosecution either. In addition, members of law enforcement entities are also allowed to commit justified homicides within certain parameters which, when met, do not usually result in prosecution; see deadly force.
Criminal homicide: Criminal homicide takes several forms and is not always an intentional crime. What type of crime committed in a homicide is determined by the state of mind of the defendant and statutes defining the crime. Murder, for example, is an intentional crime the severity of which is classified by degrees in statute. In some jurisdictions, certain types of murders automatically qualify for capital punishment[8], but if the defendant in capital cases is mentally retarded in the United States they may not be executed, for reasons described in Atkins v. Virginia, similar to those utilizing an insanity defense.
Also, a homicide that occurs during the commission of a felony may give rise to the crime of felony murder, or otherwise known as the felony murder rule. This can depend on the case, court and jurisdiction. Briefly, the felony murder rule allows those who kill or "accidentally" kill during felonies to be prosecuted with first-degree murder, even if they did not intentionally or plan premeditatively to kill anyone. This can apply not only to innocent bystanders or targets to the crime who are killed, but co-felons who are killed as well.
Additionally under homicide there are voluntary and involuntary manslaughter. These differ from murder in that voluntary manslaughter requires provocation. Involuntary manslaughter is completely unintentional, such as a car or hunting accidents. Some jurisdictions define the crime as a separate name in automobile accidents, and the Model Penal Code, which is referred to as a legal text (in limited active use), also defines the crime of negligent homicide as a killing committed negligently.
Assisting or helping in someone's suicide is also a crime, as demonstrated in California Penal Code Sec. 401[9]. If aid progresses beyond mere passive assistance, it may be re-classified as murder.