A massacre is a specific incident which involves the killing of people, although not necessarily a crime against humanity.
The modern definition of massacre as "wholesale slaughter, carnage", and the subsequent verb of this form, derive from late 16th century Middle French, evolved from Middle French "macacre, macecle" meaning "slaughterhouse, butchery." Further origins are dubious, though may be related to Latin macellum "provisions store, butcher shop."
The term is also used allegorically for events that do not involve deaths, such as the Saturday Night Massacre—the dismissals and resignations of political appointees during Richard Nixon's Watergate scandal.
Robert Melson's "basic working definition," reads, "by massacre we shall mean the intentional killing by political actors of a significant number of relatively defenseless people... the motives for massacre need not be rational in order for the killings to be intentional... Mass killings can be carried out for various reasons, including a response to false rumors... political massacre... should be distinguished from criminal or pathological mass killings... as political bodies we of course include the state and its agencies, but also nonstate actors..."
Mark Levene defines massacre historically as involving the murder of more than one individual, within an outrageous moral deficiency: "Although it is not possible to set unalterable rules about when multiple murders become massacres. Equally important is that massacres are not carried out by individuals, but by groups... the use of superior, even overwhelming force..." Levene excludes "legal, or even some quasi-legal, mass executions." He also points out that it is "...most often ... when the act is outside the normal moral bounds of the society witnessing it... In any war ... this killing is often acceptable."