Usage of the word Epic in the PPC:
1) Huge, exciting. Large-scale, big-picture, wide scope. If it involves an entire planet, a whole race of people, one little guy fighting against the establishment, galactic warfare or a Famous Last Stand, it probably counts as epic. Usually it has a connotation of 'impressive' or 'awesome' or just plain 'cool.'
2) A long literatue classic. Homer's epics come to mind, but the contemporary epic does not have to be epic poems. It is the opinion of many PPC members that the trilogy forming Lord of the Rings is an epic.
3) This is a gear tier in World of Warcraft.
4) Epic can also refer to an enormous creature in Spore.
5) Extremely long fanfic is often called 'epic' but whether it is epic fanfiction is up to debate. There are just as many digital doorstoppers are there long quality sagas. In the same way a Mary Sue can exist in the most grammar-immaculate work, Longfic can be badfic, too.