fratricide

from WordNet (r) 3.0 (2006)

fratricide
    n 1: a person who murders their brother or sister
    2: fire that injures or kills an ally [syn: {friendly fire},
       {fratricide}]
    3: the murder of your sibling

from The Collaborative International Dictionary of English v.0.48

Fratricide \Frat"ri*cide\, n. [L. fratricidium a brother's
   murder, fr. fratricida a brother's murderer; frater, fratris,
   brother + caedere to kill: cf. F. fratricide.]
   1. The act of one who murders or kills his own brother.
      [1913 Webster]

   2. [L. fratricida: cf. F. fratricide.] One who murders or
      kills his own brother.
      [1913 Webster]

from Bouvier's Law Dictionary, Revised 6th Ed (1856)

FRATRICIDE, criminal law. He who kills his brother or sister. The crime of 
such a person is also called fratricide.

from Moby Thesaurus II by Grady Ward, 1.0

19 Moby Thesaurus words for "fratricide":
      aborticide, fungicide, genocide, germicide, herbicide, homicide,
      infanticide, insecticide, matricide, microbicide, parricide,
      patricide, pesticide, regicide, rodenticide, sororicide, suicide,
      uxoricide, vermicide

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