Her husband's death reminded her of her own mortality.
mortality
/mȯr-ˈta-lə-tē/
noun
the quality or state of being mortal
the death of large numbers (as of people or animals)
death
noun
the ratio between deaths and individuals in a specified population and during a particular time period : the incidence of deaths in a given population during a defined time period (such as one year) that is typically expressed per 1000 or 100,000 individuals : death, rate
an annual mortality rate of 15 deaths per 1000 people
noun
an actuarial table based on mortality statistics over a number of years