English 101- Titling protocol
Stand-up= two feet on the deck of the board (sponge or glassed) and the body generally in an upright position with the head over the engaged foot. Hands and arms are used for little more than balance and paddling.
Prone= not standing up, but lying down with one's whole body, hence the name "Bodyboarding"~ generally on one's belly but I'll have to admit that I've tried to do it on my back with not much success. Typically the rider is holding the nose and one rail for control. Prone riders typically use hands and legs for paddling since fins make it hard to convert to "Stand-up" status, but I've seen it done- usually without fins though.
Drop Knee= or variably a raised knee, since one is down and the other is up, sort of half prone, half stand-up. It may be the best of both worlds, maybe not, since typically the rider is still wearing fins that get in the way of a full fledged "stand-up."
Boardless surfing= no need of a board of any kind, truly the purest form of wave riding- if you don't count the fins that help you catch the "whatever you call them things." Absolutely no fear of ever falling off the board, but you could still drown.
What would you call them? If you don't like the names or the images, don't look at them.;)