1. fast-spreading disease: an outbreak of a disease that spreads more quickly and more extensively among a group of people than would normally be expected
2. rapid development: a rapid and extensive development or growth, usually of something unpleasant an epidemic of civil unrest and rioting
adjective
Definition:
spreading unusually quickly and extensively: spreading more quickly and more extensively than would usually be expected Credit card crime is reaching epidemic proportions.
[Early 17th century. < French épidémique< épidémie "an epidemic" < Greek epidēmia "disease prevalent among the people" < dēmos "people"]
