regicide Meaning, Definition & Usage

  1. noun someone who commits regicide; the killer of a king
  2. noun the act of killing a king

WordNet

Reg"i*cide noun
Etymology
F. régicide; L. rex, regis, a king + caedere to kill. Cf. Homicide.
Definitions
  1. One who kills or who murders a king; specifically (Eng.Hist.), one of the judges who condemned Charles I. to death.
  2. The killing or the murder of a king.

Webster 1913