From the Anglo-Norman phrase crier havok (“cry havoc”) a signal to soldiers to seize plunder, from Old French crier (“cry out, shout”) + havot (“pillaging, looting”).
"cry-havoc." YourDictionary, n.d. Web. 19 May 2018. <http://www.yourdictionary.com/cry-havoc>.
cry-havoc. (n.d.). Retrieved May 19th, 2018, from http://www.yourdictionary.com/cry-havoc