adj. 1. Spreading rapidly and extensively by infection and affecting many individuals in an area or a population at the same time: an epidemic outbreak of influenza. 2. Widely prevalent: epidemic discontent. n. 1. An outbreak of a contagious disease that spreads rapidly and widely. 2. A rapid spread, growth, or development: an unemployment epidemic. [French épidémique, from épidémie, an epidemic, from Old French espydymie, from Medieval Latin epidēmia, from Greek epidēmiā, prevalence of an epidemic disease, from epidēmos, prevalent : epi-, epi- + dēmos, people; see dā- in the Appendix of Indo-European roots.] ep′i·demi·cal·ly adv. |
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