Thanks for a new word:
“Abseil” is the normal term in the UK, whereas “rappel” is used in the US. This technique is used by climbers, mountaineers, cavers, canyoners, search and rescue and rope access technicians to descend cliffs or slopes when they are too steep and/or dangerous to descend without protection.
Abseiling - Wikipedia
https://en.wikipedia.org/wiki/Abseiling
Abseiling: of German origin—by way of Estonia...