epidemic

1. (epidemiology) An occurrence of a disease or disorder in a human population at a frequency higher than that expected in a given time period; an episode of outbreak and subsequent high prevalence.

2. (by extension, colloquial) A heightened occurrence of anything harmful.Examples: "Even before the pandemic, the United States surgeon general, Vivek Murthy, said the country was experiencing an “epidemic of loneliness,” driven by the accelerated pace of life and the spread of technology into all of our social interactions."; "People are holding coordinated protests across UK towns and cities this weekend against what they call a “climate of fear” on the roads, and an “epidemic” of careless and dangerous driving that is curbing children’s freedoms and putting lives at risk."broadlycolloquial

3. (figurative) The spreading of an idea or belief amongst a population.Examples: "Lord Avonleigh was at once liberated from his imprisonment, well prepared to be considered, and to consider himself, a martyr to the cause of loyalty; and as the services of the rich nobleman,...his claims to notice and favour were most graciously acknowledged. Accordingly, he returned to his seat in a little fever of royal devotedness—it was the fashionable epidemic; and who coming from Whitehall could be without it?"figuratively