Wiktionary
avunculicide
n. The killing of one's uncle.
Wikipedia
Avunculicide
Avunculicide is the act of killing an uncle. The word can also refer to someone who commits such an act. The term is derived from the Latin words avunculus meaning "maternal uncle" and caedere meaning "to cut or kill". Edmunds suggests that in mythology avunculicide is a substitute for parricide. The killing of a nephew is a nepoticide.