EPIDEM'ICAL, a. [Gr. people.] Common to many people. An epidemic disease is one which seizes a great number of people, at the same time, or in the same season. Thus we speak of epidemic measles; epidemic fever; epidemic catarrh. It is used in distinction from endemic or local. Intemperate persons have every thing to fear from an epidemic influenza.

1. Generally prevailing; affecting great numbers; as epidemic rage; an epidemic evil.