From Longman Dictionary of Contemporary Englishfratricidefrat‧ri‧cide /ˈfrætrɪsaɪd/ noun [countable, uncountable] SCCthe crime of murdering your brother or sister
Examples from the Corpus
fratricide• Thus a gene for chromosomal fratricide will spread as surely as a murderer will inherit the Earth.• At least, he had saved his country from foolish fratricide by unselfishly renouncing the presidency.• The Very Model of a Man is at is best when Cain justifies his fratricide with this lethal logic.Origin fratricide (1400-1500) French Latin fratricida “brother-killer” 