"Epic" meant "historical" or "legendary" in Ancient Greek. In modern slang, "epic" denotes something grandiose, of legendary proportions. The word is often used to refer to trailer music and symphonic soundtracks, especially ones associated with fantasy or adventure, as well as fantasy-themed metal. While not a genre, such music is typically longer in length, incorporates “grand” elements such as wall-of-sound/layering, reverb, choral or orchestral accompaniment, and unconventional song structure. It generally starts relatively small, contained, and quiet, but builds to an outspread, voluminous peak.