Source : Webster's Revised Unabridged Dictionary (1913)

Massacre \Mas"sa*cre\, v. t. [imp. & p. p. {Massacred}; p. pr. &
   vb. n. {Massacring}.] [Cf. F. massacrer. See {Massacre}, n.]
   To kill in considerable numbers where much resistance can not
   be made; to kill with indiscriminate violence, without
   necessity, and contrary to the usages of nations; to butcher;
   to slaughter; -- limited to the killing of human beings.

         If James should be pleased to massacre them all, as
         Maximian had massacred the Theban legion. --Macaulay.

Massacre \Mas"sa*cre\, n. [F., fr. LL. mazacrium; cf. Prov. G.
   metzgern, metzgen, to kill cattle, G. metzger a butcher, and
   LG. matsken to cut, hew, OHG. meizan to cut, Goth.
   m['a]itan.]
   1. The killing of a considerable number of human beings under
      circumstances of atrocity or cruelty, or contrary to the
      usages of civilized people; as, the massacre on St.
      Bartholomew's Day.

Source : WordNet®

massacre
     n : the savage and excessive killing of many people [syn: {slaughter},
          {mass murder}, {carnage}, {butchery}]
     v : kill a large number of people indiscriminately; "The Hutus
         massacred the Tutsis in Rwanda" [syn: {slaughter}, {mow
         down}]