Merriam-Webster's Collegiate® Dictionary, 11th Edition
EPIDEMIC
I. adjective see: demagogue
Date: 1603
affecting or tending to affect a disproportionately large number of individuals within a population, community, or region at the same time ,
2. excessively prevalent, contagious 4 , of, relating to, or constituting an epidemic , epidemical adjective epidemically adverb epidemicity noun
II. noun
Date: 1757
an outbreak of epidemic disease, an outbreak or product of sudden rapid spread, growth, or development