Prusick knot
A Prusik is a friction hitch or knot used to attach a loop of cord around a rope, applied in climbing, canyoneering, mountaineering, caving, rope rescue, ziplining, and by arborists. The term Prusik is a name for both the loops of cord used to tie the hitch and the hitch itself, and the verb is “to prusik” or “prusiking” (i.e. using a Prusik to ascend). More casually, the term is used for any friction hitch or device that can grab a rope . Due to the pronunciation, the word is often misspelled Prussik, Prussick, or Prussic.