Epidemic/Pandemic

Is it a pandemic or an epidemic of flu that hits the headines from time to time, with journalists

speculating that it could wipe out the human race?

Well, the words mean much the same thing - an outbreak of disease. They have the same ending (-demic, which is derived from the Greek demos meaning people). However, a pandemic affects people all over the world (pan- meaning all), whereas epidemics (epi- meaning upon or among) are usually thought of as affecting a smaller group of people (all pupils at a school, all people in a particular area or even the population of a whole country).

These words are used by epi-demiologists - who study factors affecting the health and illness of populations - to describe how a disease such as flu (or, in the olden days, bubonic plague) is spreading around the world. The words imply the scale, rather than severity, of the problem.