The Oxford English Dictionary's first citation for the term is a 1953 article from the Birmingham News, and it appears again in 1959 in the New Statesman. The term was used to refer to the "megadeath intellectuals", the group of thinkers surrounding RAND Corporation strategist Herman Kahn. The concept was notably discussed in Kahn's 1960 book, On Thermonuclear War.
In the book, Kahn observes that "It was difficult for people to distinguish in the early 1950s between 2 million deaths and 100 million deaths. Today, after a decade of pondering these problems, we can make such distinctions perhaps all too clearly. Most of the decision makers and planners who have been facing the prospects of a thermonuclear war would find it difficult to distinguish between zero and two million deaths and very easy to distinguish between two million and a hundred million deaths." In a table, Kahn outlines "tragic but distinguishable postwar states" in which the number of deaths range from 2 million to 160 million, and asks "will the survivors envy the dead ?".
Though the term was created in order to discuss the likely consequences of conducting nuclear war, such a large number of deaths could also be associated with other nation-state weapons of mass destruction. An extension of this is the term Gigadeath describing deaths in billions such as projected by retired Artificial Intelligence researcher Hugo de Garis as the consequence of an inevitable future war between proponents and opponents of Artificial Intelligent entities. He calls this conflict The Artilect War.