epidemical, a. [L. epidemus, Gr. , , among the people, epidemic; in + people: cf. F. épidémique. Cf. Demagogue.].
Common to, or affecting at the same time, a large number in a community; -- applied to a disease which, spreading widely, attacks many persons at the same time; as, an epidemic disease; an epidemic catarrh, fever, etc. See Endemic. [1913 Webster]
Spreading widely, or generally prevailing; affecting great numbers, as an epidemic does; as, epidemic rage; an epidemic evil. [1913 Webster]
"It was the epidemical sin of the nation."