(in mountaineering) the act or method of moving down a steep incline or past an overhang by means of a double rope secured above and placed around the body, usually under the left thigh and over the right shoulder, and paid out gradually in the descent.
verb (used without object)
to descend by means of a rappel.
Origin: 1930–35; < French: mountaineering term, literally, a recall. See repeal
1931, "mountaineering technique for descending steep faces," from Fr. rappel, lit. "recall," from O.Fr. rapel, from rapeler "to recall, summon" (see repeal). The verb is first recorded 1957. The same word had been borrowed earlier (1848) to mean "a drum roll to summon soldiers."