1. The number of deaths in the population divided by the average population (or the population at midyear) is the crude death rate. In 1994, for example, the crude death rate per 1,000 population was 8.8 in the united states, 7.1 in Australia, etc. A death rate can also be tabulated according to age or cause. The ratio of deaths in an area to the population of that area; expressed per 1000 per year. (biology-online.org)
2. Usually measured by deaths per 1000 of population, the death rate is the number of a species which die, usually measured along side the birth Rate to determine long term population trends. (biology-online.org)
3. The ratio of deaths to the population of a particular area during a particular period of time, usually calculated as the number of deaths per one thousand people per year. (Google Dictionary)
See also Mortality rate.