epidemic
/ˌɛpɪˈdɛmɪk/
(especially of medicine) of disease or anything resembling a disease; attacking or affecting many individuals in a community or a population simultaneously
中文释义：流行性的；传染的
The epidemic disease spread rapidly through the population.
这种流行病在人群中迅速传播。
Obesity has become an epidemic problem in many developed countries.
肥胖在许多发达国家已成为一个流行性问题。