infant mortality
noun /ˌɪnfənt mɔːˈtæləti/
  /ˌɪnfənt mɔːrˈtæləti/
[uncountable]- the death of children under the age of one year婴儿死亡率:1岁以下儿童的死亡 - the decline of infant mortality in the 20th century20世纪婴儿死亡率的下降 
- the infant mortality rate婴幼儿死亡率 
 
- the decline of infant mortality in the 20th century