"unnecessary, indiscriminate killing of human beings," sometimes also applied to wholesale slaughter of animals, 1580s, from French massacre "wholesale slaughter, carnage," from Old French macacre, macecle "slaughterhouse; butchery, slaughter," which is of unknown origin; perhaps related to Latin macellum "provisions store, butcher shop," which probably is related to mactāre "to kill, slaughter."
"to kill (many beings) indiscriminately," commonly in reference to those who are not in a condition to defend themselves, 1580s, from French massacrer "to slaughter" (16c.), from massacre (n.) "wholesale slaughter, carnage" (see massacre (n.)). Sometimes 17c.-18c. merely "to murder cruelly," without reference to number. Related: Massacred; massacring.
"organized massacre in Russia against a particular class or people, especially the Jews," 1882, from Yiddish pogrom, from Russian pogromu "devastation, destruction," from po- "by, through, behind, after" (cognate with Latin post-; see post-) + gromu "thunder, roar," from PIE imitative root *ghrem- (see grim).
"great destruction by bloody violence, massacre," c. 1600, from French carnage (16c.), from Old Italian carnaggio "slaughter, murder," from Medieval Latin carnaticum "flesh," from Latin carnaticum "slaughter of animals," from carnem (nominative caro) "flesh," originally "a piece of flesh" (from PIE root *sker- (1) "to cut"). In English it has been always used more often of slaughters of men than of beasts. Southey (1795) tried to make a verb of it.
mid-14c., mortalite, "condition of being subject to death or the necessity of dying," from Old French mortalite "massacre, slaughter; fatal illness; poverty; destruction" (12c.) and directly from Latin mortalitem (nominative mortalitas) "state of being mortal; subjection to death," from mortalis "subject to death, mortal," from PIE root *mer- "to rub away, harm" (also "to die" and forming words referring to death and to beings subject to death).
Meaning "widespread death, numerousness of deaths; plague" is from c. 1400; meaning "number of deaths from some cause or in a given period" is from 1640s, later especially in proportion to population.
mid-13c., "sacrifice by fire, burnt offering," from Old French holocauste (12c.), or directly from Late Latin holocaustum, from Greek holokauston "a thing wholly burnt," neuter of holokaustos "burned whole," from holos "whole" (from PIE root *sol- "whole, well-kept") + kaustos, verbal adjective of kaiein "to burn" (see caustic).
Originally a Bible word for "burnt offerings," given wider figurative sense of "massacre, destruction of a large number of persons" from 1670s. The Holocaust "Nazi genocide of European Jews in World War II," first recorded 1957, earlier known in Hebrew as Shoah "catastrophe." The word itself was used in English in reference to Hitler's Jewish policies from 1942, but not as a proper name for them.
English chronicler Richard of Devizes in his contemporary account of the coronation of Richard I in 1189 used the word holocaust when he described the mass murder of the Jews of London, although he meant it as "a sacrificial offering."