Source : Webster's Revised Unabridged Dictionary (1913)

Slaughter \Slaugh"ter\, n. [OE. slautir, slaughter, slaghter,
   Icel. sl[=a]tr slain flesh, modified by OE. slaught, slaht,
   slaughter, fr. AS. sleaht a stroke, blow; both from the root
   of E. slay. See {Slay}, v. t., and cf. {Onslaught}.]
   The act of killing. Specifically:
   (a) The extensive, violent, bloody, or wanton destruction of
       life; carnage.

             On war and mutual slaughter bent.    --Milton.
   (b) The act of killing cattle or other beasts for market.

   Syn: Carnage; massacre; butchery; murder; havoc.

Slaughter \Slaugh"ter\, v. t. [imp. & p. p. {Slaughtered}; p.
   pr. & vb. n. {Slaughtering}.]
   1. To visit with great destruction of life; to kill; to slay
      in battle.

            Your castle is surprised; your wife and babes
            Savagely slaughtered.                 --Shak.

   2. To butcher; to kill for the market, as beasts.

Source : WordNet®

slaughter
     n 1: the killing of animals (as for food)
     2: a sound defeat [syn: {thrashing}, {walloping}, {debacle}, {drubbing},
         {trouncing}, {whipping}]
     3: the savage and excessive killing of many people [syn: {massacre},
         {mass murder}, {carnage}, {butchery}]

slaughter
     v 1: kill (animals) usually for food consumption; "They
          slaughtered their only goat to survive the winter" [syn:
           {butcher}]
     2: kill a large number of people indiscriminately; "The Hutus
        massacred the Tutsis in Rwanda" [syn: {massacre}, {mow
        down}]