Definition of "fratricide"

The new accusation brought by Urban against Manfred of murdering his sister-in-law's embassador – it may be observed that, tacitly, he acquits him of parricide, fratricide, and nepoticide – requires a little explanation.

1856, Mrs. William Busk, Mediæval Popes, Emperors, Kings, and Crusaders: Or, Germany, Italy and Palestine, from A.D. 1125 to A.D. 1268‎, volume IV, London: Hookham and Sons, page 294

Terms related to familicide include filicide (the killing of one's child or children), uxoricide (the killing of one's wife), fratricide or sororicide (the killing of one's brother or sister), avunculicide (the killing of one's uncle), and nepoticide (the killing of one's nephew).

2014, Albert Lee Strickland, “Familicide”, in Michael John Brennan, editor, The A–Z of Death and Dying: Social, Medical, and Cultural Aspects, Santa Barbara, Calif.: Greenwood Publishing Group, pages 205–206

From January on, Third Army also spent a good deal of energy trying to solve the problem of fratricide, the killing or injuring of one's own forces by what is ironically called 'friendly fire,' […]

1999, Richard M. Swain, Lucky War: Third Army in Desert Storm, DIANE Publishing, page 180

Such a press of arms invites many opportunities for unintentional fratricide.

2007 September 25, Bungie, Halo 3, v1.0, Microsoft Game Studios, Xbox 360, level/area: Terminal Six (Legendary)

Can Signorio was twice a fratricide, the last time when he lay upon his death-bed: his tomb bears upon its gables the images of six virtues, — Faith, Hope, Charity, Prudence, and (I believe) Justice and Fortitude.

1853, John Ruskin, “Roman Renaissance”, in The Stones of Venice, volume III (The Fall), London: Smith, Elder, and Co., […], § LVI, page 73

The conversion of Russia to Christianity was effected, it would seem by a monster of cruelty and lust. That Vladimir (980–1015) was a fratricide, who maintained 3,500 concubines, has not prevented his canonization as a saint.

1936, H. A. L. Fisher, A History of Europe, Edward Arnold Publishers, page 376