rappel
n.
A descent of a vertical surface, as a cliff or wall, by sliding down a belayed rope that is passed under one thigh and over the opposite shoulder or through a device that provides friction, typically while facing the surface and performing a series of short backward leaps to control the descent.
intransitive verb
To descend from a steep height by this method.
n.
The roll or beat of the drum to call soldiers to arms.