1) Death 2) Decease 3) The death of a million people 
Megadeath (or megacorpse) is a term for one million deaths by nuclear explosion. The term was used by scientists and thinkers who strategized likely outcomes of all-out nuclear warfare. 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 ter....
[n] - the death of a million people
noun the death of a million people; `they calibrate the effects of atom bombs in megadeaths`