The American Heritage Dictionary (5 ed.). Random House Publishing Group. 2012. ISBN9780553583229. Retrieved 10 September 2017. ("The killing of another person without justification or excuse, especially the crime of killing a person with malice aforethought or with recklessness manifesting extreme indifference to the value of human life.")
merriam-webster.com
"Murder". Merriam-Webster. Archived from the original on 2 October 2017. Retrieved 10 September 2017.