L.R.
Isn't it a concern for you that during its "information session" the school representatives themselves did not answer this question? Did they assume everyone in the room knew what they meant? Did you ask them? It's fine to do your independent research, but shouldn't the school be able to explain its educational approach to you in detail? If they can't explain it so anyone can understand it, how can they teach it?
If you're simply worried about being embarrassed to say "I don't know what you really mean by 'classical education,'" please don't be embarrassed. If the school's representatives make you feel small or act sniffy when you say that -- well, ask yourself if it's really the place for your son and your family.