epidemic

epidemic /-dem″ik/ [Gk, epi + demos, people] , 1. adj., affecting a significantly large number of people at the same time. 2. n., a disease that spreads rapidly through a demographic segment of the human population, such as everyone in a given geographic area, a military base, or similar population unit, or everyone of a certain age or sex, such as the children or women of a region. 3. n., a disease or event whose incidence is beyond what is expected. Compare endemic, epizootic, pandemic.