chockstone
nounUK /ˈtʃɒkstəʊn/ · US /ˈt͡ʃɑkstoʊn/
Etymology From chock + stone. The climbing sense derives from the wedges' use as artificial chockstones.
1
A stone, ranging in size from a boulder to a pebble, which has become wedged in a vertical fissure or cleft.
- In these coldest hours before dawn, from three until six, I take up my knife again and hack at the chockstone. I continue to make minimal but visible progress in the divot.2004, Aron Ralston, 127 Hours: Between a Rock and a Hard Place, Simon and Schuster, published 2011, page 68: