Learner's definition of MORTALITY
the quality or state of being a person or thing that is alive and therefore certain to die
the quality or state of being mortal
the death of a person, animal, etc.
the number of deaths that occur in a particular time or place
a decrease in cancer mortality [=a decrease in the number of people dying from cancer]
The government is trying to reduce infant mortality. = The government is trying to reduce the mortality rate among infants. [=trying to reduce the number of infants who die each year]