mor ‧ tal ‧ i ‧ ty /mɔːˈtæləti, mɔːˈtælɪti $ mɔːr-/ BrE AmE noun ( plural mortalities )
1 . [uncountable] ( also morˈtality ˌrate / $ .'.../) the number of deaths during a particular period of time among a particular type or group of people:
Mortality from heart disease varies widely across the world.
infant/child/maternal/adult mortality
an appallingly high infant mortality rate (=number of babies who die)
2 . [uncountable] the condition of being human and having to die OPP immortality :
My mother’s death forced me to face the fact of my own mortality.
3 . [countable] technical a death:
mortalities from cancer