Definition of mortality
1
:the quality or state of being mortal
- Her husband's death reminded her of her own mortality.
2
:the death of large numbers (as of people or animals)
- trying to reduce infant mortality
4
:the human race
- that natural extinction to which all mortality is subject
- —Thomas Paine
5 a
:the number of deaths in a given time or place
- The mortality among the infected mounted daily.
b
:the proportion of deaths to population
- a brain infection with a mortality rate of about 30 percent
- —Jane E. Brody
c
:the number lost or the rate of loss or failure
- the mortality rate of small businesses
