birth·rate also birth rate (bûrth'rāt') n. The ratio of total live births to total population in a specified community or area over a specified period of time. The birthrate is often expressed as the number of live births per 1,000 of the population per year. Also called natality.
na·tal·i·ty (nā-tāl'ĭ-tē, nə-) n.
pl.na·tal·i·ties See birthrate.