The Difference between a Pandemic and an Epidemic

Both pandemic and epidemic refer to an occurrence in which a disease spreads quickly and affects a lot of people.

An epidemic is an occurrence of a rapidly spreading disease that affects many people. A pandemic, in comparison, is an occurrence of a rapidly spreading disease that affects a large proportion of the population and has spread to many different geographic regions.

A pandemic is a very bad epidemic.

There is no set point at which an epidemic is officially called a pandemic, and so sometimes an outbreak of a disease is called both.

I hope this helps.