This article is about the act of ending a living being's life. For other meanings, see Kill (disambiguation) or Killing (disambiguation)
To kill, killing or to have killed means to cause the death of a living organism.
The act of killing an animal or plant life form can be said to have occurred when an outside force, usually another life form, has done something to cause it to die. This may be a result of several actions:
Prime quality studies about the psychology related to killing can be found on the website of the Killology Research Institute.

a deliberate action such as war
in the case of animals, slaughter; see slaughterhouse
the result of a criminal act, the action or fault of another human being, see homicide and murder
the results of an accident, such as a car crash. See negligent homicide
an organism eating another organism