Definition: Infant mortality rate
United Nations terminology
A vital statistics summary rate based on the number of infant deaths occurring during the same period of time, usually a calendar year, i.e., the number of deaths under one year of age occurring in a given geographical area during a given year, per 1,000 live births occurring among the population of the given geographical area during the same year.
United Nations, "Handbook on Training in Civil Registration and Vital Statistics Systems", Studies in Methods, Series F, No. 84, New York, 2002