n The quality or condition of being prevalent; superior strength, force, or influence; general existence, reception, or practice; wide extension; as the prevalence of virtue, of a fashion, or of a disease; the prevalence of a rumor.
n (epidemiology) The total number of cases of a disease in the given statistical population at a given time.
n (epidemiology) The total number of cases of a disease in the given statistical population at a given time, divided by the number of individuals in the population.