Yeah, I'm referring to the Ohio thing.  Knowing how the media likes to butcher terminology like "assault weapons" and "terror attacks", I was just wondering if they were doing the same thing with the Ohio situation for sensational purposes?

AFAIK, "mass killing" involves 3 or more homicides in one event, or a closely connected series of events. "serial killing" involves 2 or more victims by a single killer at different times and/or places.

Almost correct - I think there has to be a definitive "cooling off" period between killings for the person to actually be classified as a "serial" killer. So going to Walmart, killing some folks, then driving to a neighboring county and shooting up your favorite bar would not count as a "serial killing" by FBI profilers.

I thought that maybe because they were related that it fit a pattern.

FBI definition:

A mass murder as murdering four or more persons during an event with no "cooling-off period" between the murders. A mass murder typically occurs in a single location where one or more people kill several others.

A serial killer is a person who murders three or more people, usually in service of abnormal psychological gratification, with the murders taking place over more than a month and including a significant break (a "cooling off period") between them

Thanks.