parricide (n.)

1. "person who kills a parent or near relative" (1550s), also 2. "act of killing parent or near relative" (1560s), both from Middle French parricide (13c. in sense 1, 16c. in sense 2), from 1. Latin parricida, 2. Latin parricidium, probably from parus "relative" (of uncertain origin, but compare Greek paos, peos "relation," Sanskrit purushah "man") + 1. cida "killer," 2. cidium "killing," both from caedere "to kill, to cut down" (from PIE root *kae-id- "to strike"). Old English had fæderslaga.