Sculling - moving your hand back and forth in the water, at your hips, your shoulder or over your head to keep your body balanced in the water while providing some propulsion. More specifically, this means to gently propel yourself through the water by moving your hands close to and just under your hips, using the figure-eight pattern. Basically, just easily push yourself through the water on your back.
Distance per Stroke (DPS) - The number of strokes (left and right arm combined) that it takes to go 25 yards. Example, a DPS of 25 means to try to swim 25 yards with 25 left and right arm strokes.