Intermediate
A rider who has a firm, balanced seat, is confident and in control at all paces (including posting trots, canters and gallops) in open country, and knows how to use the aids in all paces. An intermediate rider rides on a regular basis and may have begun specialized training such as jumping or dressage.
Advanced
All of the above, plus an independent seat, soft hands, the capability of handling a spirited horse in open country, and in-depth specialized training such as jumping or dressage.