Xc - normal trails. Technical not too big in the way of drops and jumps
All mountain -...ummm....kind of taken on a all day epic mountain ride kind of thing. 5x5 or 6x6 travel, can take good sized hits and drops but the bike is still reasonably pedalable
Freeride - drops, stunts. I liken this to the bmxing of mountain biking. Sessioning stuff, if you see a drop, jumps or steep rockface you ride it. Walk back up and ride it again