ETYM French, from Late Lat. mazacrium; cf. Prov. German metzgern, metzgen, to kill cattle, German metzger a butcher, and LG. matsken to cut, hew, Old High Germ. meizan to cut, Goth. máitan.
The wanton killing of many people; SYN. mass murder.

ETYM Old Eng. slautir, slaughter, slaghter, Icel. slâtr slain flesh, modified by Old Eng. slaught, slaht, slaughter, from as. sleaht a stroke, blow; both from the root of Eng. slay. Related to Slay, Onslaught.
1. The killing of animals (as for food).
2. The savage and excessive killing of people; SYN. carnage, butchery.