Rappel
Rappelling is the process of descending a fixed rope by making a controlled slide down the rope, usually with a mechanical braking device, like a rappel device, Figure 8 descender, or a carabiner brake fashioned with up to six carabiners. Rappelling is one of the most dangerous aspects of climbing because the climber relies solely on his safety system and equipment, including his ropes, harness, rappel device, as well as the anchors that the ropes are threaded through. American climbers often shorten the word to “rap,” as in “We did two raps off Moses” or “Do we have to rap off this route?” In Britain rappelling is called abseiling, which is often shortened to “ab.”
