mortality
n[U]
1 state of being mortal 不免一死.
2 (also mor`tality rate) number of deaths in a specified period of time 死亡率
Infant mortality (ie The rate at which babies die) was 20 deaths per thousand live births in 1986. 1986年的婴儿死亡率为生育成活率的千分之二十.
3 large number of deaths caused by a disease, disaster, etc (疾病、 灾难等造成的)大量死亡.