Con

Con = Short form of "Convention" 

Refers to real-life gatherings of fans, sometimes officially endorsed (with official guests!), sometimes not, but gathering together to meet and exchange over a period of several days. Cons may be small (no more than 25 people) or large (no less than 25,000 people); dedicated to one specific fandom or welcoming them all; gen, slash, or bi-genre in nature; and/or anything else the hosts can think of. For example, Comic Con is an especially popular con for both fans and official guests (actors, writers, artists, other Powers-That-Be, etc...) held annually in San Diego, California, USA.