The death rate is the number of deaths per 1,000 individuals in a population in a year.
This term refers to the measure of the number of deaths (in general or due to specific causes) in some particular population scaled to size over time.
Life Expectancy: It's an estimate on how long someone may live based on various demographic factors like their current age and sex.
Infant Mortality Rate: This term refers specifically to the death rate during the first year of life.